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26 CHAPTER 3 EFFECTS OF SUBSURFACE DRAINAGE ON CONCRETE PAVEMENTS DESCRIPTION OF LTPP EXPERIMENT SPS-2 The SPS-2 experiment (Strategic Study of Structural Fac- tors for Rigid Pavements) was designed to assess the influ- ence of the following factors on the performance of jointed concrete pavements: ⢠Concrete thickness, ⢠Concrete flexural strength, ⢠Base type, ⢠Lane width, ⢠Subdrainage, ⢠Climate, ⢠Subgrade, and ⢠Truck traffic level. The Strategic Highway Research Programâs original exper- imental design and research plan for SPS-2 are described in Reference 5. The design factorial for the SPS-2 experiment is shown in Table 22. The first two digits (02) of the number shown within each cell signify the SPS-2 experiment, and the last two digits signify the test section design. The base types listed in Table 22 are dense-graded aggre- gate, lean concrete base, and permeable asphalt treated. Other than some thickness deviations, the pavement struc- tures actually constructed conform to the experiment design shown in Table 22, with one important exception: which sec- tions are drained and which are not. The field inspection of the drains, discussed in more detail later in this chapter, found several instances of the following discrepancies: ⢠Some pavement sections were found to have drains installed even though they should not, according to the experiment design; ⢠Some pavement sections should have had drains installed, but the presence of the drains was not confirmed in the field inspections; and ⢠Some pavement sections should and do have drains installed, but the drains do not appear to be functioning effectively. The site factorial for the SPS-2 experiment is shown in Table 23. Note that although two or more states built the same designs in a few cases, these are not replicates in the true sense of the word, as the sites are not identical in terms of the concomitant variable, truck traffic level, nor are their climates identical. The California SPS-2 project was opened to traffic in October 2000, and little information about it was available in the database as of June 2001. The western LTPP regional center reports that the soil is coarse (silty sand). The states listed in the upper row for each subgrade type in Table 23 are those that built designs 0201 through 0212. The pavement designs in the core SPS-2 experiment con- structed at these sites are shown in Table 24. The states listed in the lower row for each subgrade type in Table 23 are those that built designs 0213 through 0224. These pavement designs are shown in Table 25. The geographic distribution of the fourteen SPS-2 sites is illustrated in Figure 5. Location data for the SPS-2 projects are given in Table 26. Climate Characterization The climatic distribution of the SPS-2 sites was determined by extracting the latitude and longitude for each site from the LTPP database, searching the National Oceanic and Atmo- spheric Administration (NOAA) database for the weather sta- tion nearest the SPS-2 site, extracting the 30-year average monthly precipitation levels and average monthly tempera- tures for the weather station, and calculating the average annual precipitation and average annual temperature for each. These data are provided in Table 27. The distribution of the SPS-2 sites with respect to average annual precipitation and temperature are illustrated in Figure 6. The need for subsurface drainage can be quantified with respect to a design rainfall, that is, one of a given magnitude, duration, and frequency. For example, a 1-year, 1-hour rainfall is an amount of rainfall that at a particular location lasts 1 hour and occurs, on average, once a year. Rainfall frequency infor- mation is not easily accessed in tabular form but rather must be obtained from contour maps. The 1-year, 1-hour rainfalls for the SPS-1 and SPS-2 sites were determined from contour maps in Reference 2. In the absence of rainfall frequency information, it is pos- sible to estimate the 1-year, 1-hour rainfall as a function of the average annual precipitation, which is more readily known. As was shown in Figure 3, there is an evident (although non- linear) correlation between average annual precipitation
and the 1-year, 1-hour rainfall for nearly all of the SPS-1 and SPS-2 sites. The exceptions are the three SPS-1 sites closest to the Gulf coast (Texas, Louisiana, and Florida), for which the correlation curve seems to be shifted upwardâthat is, higher 1-year, 1-hour rainfall at those sites than for noncoastal sites with similar levels of average annual precipitation. Test Section Layouts and Pavement Structures The station limits, layer thicknesses, and material types for each of the SPS-2 test sections were extracted from the 27 SPS_PROJECT_STATIONS and TST_L05B data tables in the LTPP database. The thicknesses in the TST_L05B table represent the LTPP regional data collection centersâ best esti- mates of the as-constructed layer thicknesses and materials. (The test section layout and pavement layer data are given in Appendix B. For the California site, as-constructed layer thickness estimates are not yet known, so the design layer thicknesses are shown.) The layout diagrams also indicate which sections are supposed to be drained and which are not and the locations of edgedrain outlets inspected in the field inspections conducted in late 2001 and early 2002. Undrained Drained Slab thickness, inches Flexural strength, psi Lane width, ft Dense-graded aggregate base Lean concrete base Permeable asphalt-treated base 12 0201 0205 0209 550 14 0213 0217 0221 12 0214 0218 0222 8 900 14 0202 0206 0210 12 0215 0219 0223 550 14 0203 0207 0211 12 0204 0208 0212 11 900 14 0216 0220 0224 TABLE 22 SPS-2 design factorial Wet Dry Freeze Nonfreeze Freeze Nonfreeze OH, KS NC Fine subgrade MI, IA, ND AR DE NV, WA CA Coarse subgrade WI CO AZ TABLE 23 SPS-2 site factorial Undrained Drained Slab thickness, inches Flexural strength, psi Lane width, ft Dense-graded aggregate base Lean concrete base Permeable asphalt-treated base 12 0201 0205 0209 550 14 12 8 900 14 0202 0206 0210 12 550 14 0203 0207 0211 12 0204 0208 0212 11 900 14 TABLE 24 Core SPS-2 test sections built at California, Delaware, Kansas, Nevada, North Carolina, Ohio, and Washington sites
The presence of filter fabric below the permeable asphalt- treated base in the SPS-2 test sections designed to be drained is summarized in Table 28. This summary is based on infor- mation in the TST_L05B and SPS2_LAYER data tables and the LTPP regional support centersâ responses to an LTPP Data Analysis/Operations Feedback Report (KTH-2, 11 June 2002) submitted by the NCHRP 1-34C research team. In nearly all cases, no filter fabric was used below the permeable asphalt-treated base in the SPS-2 test sections designed to be drained. The exceptions are the four Arkansas SPS-2 sections and the four Iowa SPS-2 test sections with this base type. The four Arkansas sections have a geotextile below the PATB, according to the regional support center, although this is not reflected in the national LTPP database as of release 12.0. Traffic Characterization The 18-kip-equivalent single-axle (ESAL) levels at the SPS-2 sites were determined by extracting the following data from the LTPP database: ⢠ESAL estimates obtained from traffic monitoring dur- ing the experiment from the TRF_MON_EST_ESAL data table; and ⢠Axle load distributions obtained from traffic monitor- ing during the experiment from the TRF_MONITOR_ AXLE_DISTRIBUTION data table. Axle load distribution data were available for eleven of the fourteen SPS-2 sites. Data were not available for the sites in California, North Dakota, and Wisconsin. ESALs were calculated for the years in which axle load distribution data were available, using (1) the number of axles reported in each load range in the distribution and 28 (2) load equivalency factors calculated as a function of the as-constructed concrete slab thickness. For years during the experiment in which axle load distribution data were not avail- able, ESAL estimates from TRF_MON_ EST_ESAL table were used if available. In a few cases, linear interpolations of annual ESALs were necessary for years in which no axle load distribution or ESAL data were available. It was also necessary in a few cases to extrapolate a year or two before or after the years for which data were available. A growth rate of 5 percent was used for these extrapolations. From the annual ESAL estimates for the different test sec- tions at each site, the average annual ESALs for the site were calculated. The average annual ESALs estimates for each site were used to calculate accumulated ESAL estimates from the date of opening to traffic to several dates of profile, faulting, and cracking measurements. The measurement dates were those on which measurements were obtained for most or all of the test sections at the site. When more than one such date occurred in the same year for a particular type of measure- ment, one of the dates was selected for use. The annual and accumulated ESAL estimates for each site with data avail- able are provided in Appendix B. The age of each SPS-2 site and the accumulated rigid pavement ESALs for each site with traffic data available, as of the latest date of condition measurements available for this study, are shown in Table 29. Also shown is the accumulated ESALs divided by the age, which gives a rough estimate of the average annual ESAL level during the time that each site has been in service. The ages and accumulated ESALs at the SPS-2 sites are also illustrated in Figure 7. The vertical scale of this graph was chosen to be compatible with the range of flexible pave- ment ESALs for the SPS-1 sites (shown in Chapter 2). Tak- ing into consideration the fact that one flexible pavement ESAL is roughly equivalent to 1.5 rigid pavement ESALs, it is nonetheless clear that the SPS-2 sites have, on average, Undrained Drained Slab thickness, inches Flexural strength, psi Lane width, ft Dense-graded aggregate base Lean concrete base Permeable asphalt treated base 12 550 14 0213 0217 0221 12 0214 0218 0222 8 900 14 12 0215 0219 0223 550 14 12 11 900 14 0216 0220 0224 TABLE 25 Core SPS-2 test sections built at Arizona, Arkansas, Colorado, Iowa, Michigan, North Dakota, and Wisconsin sites
29 Figure 5. SPS-2 sites.
received more than double the ESALs that the SPS-1 sites have received. SPS-2 Construction Some information on construction of the SPS-2 sites is available in the construction reports prepared by the LTPP regional support centers. Construction deviation reports were obtained for seven of the fourteen SPS-2 sites: Arizona, Arkansas, Colorado, Delaware, Nevada, North Carolina, and 30 Washington. The information available on construction devi- ations is summarized in Table 30. FIELD INSPECTIONS OF DRAINS AT SPS-2 SITES Video inspections of the longitudinal subdrains and outlets at the SPS-2 sites were conducted in late 2001 and early 2002, under an FHWA contract with NCHRP support, using the same procedure as that used at the SPS-1 sites (described SHRP ID State County Nearby city or town Route Latitude Longitude 040200 AZ Maricopa Phoenix I-10 33.45 112.74 050200 AR Saline Benton I-30 34.54 92.68 060200 CA* Merced Turlock SR 99 37.42 120.77 080200 CO Adams Denver I-76 39.97 104.79 100200 DE Sussex Ellendale US 113 38.87 75.44 190200 IA Polk Des Moines US 65 41.65 93.47 200200 KS Dickenson Salina I-70 38.97 97.09 260200 MI Monroe Toledo, Ohio US 23 41.75 83.70 320200 NV Lander Battle Mountain I-80 40.72 117.04 370200 NC Davidson Lexington US 52 35.87 80.27 380200 ND Cass Fargo I-94 46.88 97.17 390200 OH Delaware Delaware US 23 40.38 83.06 530200 WA Adams Ritzville US 395 47.06 118.42 550200 WI Marathon Wausau SR 29 44.49 89.23 * Route, county, and nearby town based on location indicated by latitude and longitude data. TABLE 26 SPS-2 location data SPS-2 Site Nearest Weather Station State State Code Latitude (degrees) Longitude (degrees) ID Name Latitude (degrees) Longitude (degrees) Average Annual Precipitation (inches) Average Annual Temperature (degrees F) AZ 04 33.45 112.74 029287 Wickenburg 33.59 112.44 12.20 66.10 AR 05 34.54 92.68 030130 Alum Fork 34.48 92.52 53.68 61.70 CA 06 37.42 120.77 26 (estimate) 61 (estimate) CO 08 39.97 104.79 055116 Longmont 40.11 105.06 13.60 48.80 DE 10 38.87 75.44 072730 Dover 39.09 75.31 44.14 56.30 IA 19 41.65 93.47 130241 Ankeny 3 S 41.41 93.36 32.18 48.10 KS 20 38.97 97.09 141559 Clay Center 39.23 97.07 30.48 55.20 MI 26 41.75 83.70 200032 Adrian 2 NNE 41.55 84.01 34.15 47.90 NV 32 40.72 117.04 263245 Golconda 40.57 117.29 7.58 50.00 NC 37 35.87 80.27 319675 Yadkinville 6 E 36.08 80.31 45.07 58.00 ND 38 46.88 97.17 321686 Colgate 47.14 97.39 17.76 40.40 OH 39 40.38 83.06 334942 Marion 2 N 40.37 83.08 36.91 49.20 WA 53 47.06 118.42 454679 Lind 3 NE 47.00 118.35 9.37 49.70 WI 55 44.49 89.23 022462 Rosholt 9 NNE 44.46 89.15 32.91 42.90 TABLE 27 Average annual precipitation and temperature levels for weather stations nearest SPS-2 sites
31 32 48 64 80 0 21 42 63 Mean annual precipitation (inches) M ea n an nu al te m pe ra tu re (o F) AZ NV WA CO CA KS ND WI IA MI OH AR DE z Figure 6. Distribution of SPS-2 sites with respect to precipitation and temperature. Sections with drained permeable asphalt-treated base Section number State 0209 0210 0211 0212 CA 06 no no no no DE 10 no no no no KS 20 no no no no NV 32 no no no no NC 37 no no no no OH 39 no no no no WA 53 no no no no Section number 0221 0222 0223 0224 AZ 04 no no no no AR 05 yes* yes* yes* yes* CO 08 no no no no IA 19 yes yes yes yes MI 26 no no no no ND 38 no no no no WI 55 no no no no * The regional support center reports that geotextile was placed below the PATB, although this is not reflected in LTPP database release 12.0. TABLE 28 Presence of filter fabric below permeable-asphalt treated base in SPS-2 sections designed to be drained
in Appendix A). The completed data forms for each site were furnished to the NCHRP Project 1-34C research team for use in this study. Highlights of the inspections are summarized in Appendix B. The test section layout diagrams in Appen- dix B show the locations of the edgedrain outlets inspected. Observations on Results of Field Inspections A summary of the drains inspected and not inspected is given in Table 31. In cases where an outlet was located out- 32 side the limits of any test section, it was assumed to be asso- ciated with the nearest test section. Just as with the SPS-1 inspections, instances of the following discrepancies were found in the SPS-2 inspections: ⢠Some instances of test sections that should not be drained (test sections numbered 0201 through 0208 or 0213 through 0220, depending on the site), but at which lateral outlets were found and marked for inspection. These are indicated by a âyâ in some cells in the first eight test section columns in Table 31. Note that for the Arkansas, State Age, years Accumulated rigid pavement ESALs, millions Accumulated ESALS Divided by age Arizona 7.18 8.78 1.22 Arkansas 5.04 10.89 2.16 California Data unavailable Data unavailable Data unavailable Colorado 6.78 2.14 0.32 Delaware 4.60 2.00 0.43 Iowa 5.47 0.38 0.07 Kansas 8.78 6.52 0.74 Michigan 6.46 11.48 1.78 Nevada 5.64 4.45 0.79 North Carolina 6.90 8.98 1.30 North Dakota 5.73 Data unavailable Data unavailable Ohio 4.51 2.83 0.63 Wahington 4.66 1.61 0.35 Wisconsin 2.60 Data unavailable Data unavailable Average 6.00 5.46 0.89 TABLE 29 Age and accumulated flexible pavement equivalent standard axle loads (ESALs) of SPS-2 sites at time of analysis 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 0 1 2 3 4 5 6 7 8 9 10 Age (years) Ac cu m ul at ed ri gi d pa ve m en t E SA Ls (m illi on s) Figure 7. Age versus accumulated rigid ESALs for SPS-2 sites with traffic data available.
33 SHRP ID State Problem or Deviation 040200 AZ Cracking developed immediately in the PCC1 surfacing in those sections placed over the LCB2. This only occurred in the passing lane. The 900-psi concrete strengths were actually in the low 800âs. The 550-psi and 900-psi one-year strengths are relatively close together. 050200 AR No major deviations, although at station 2+50 on section 8, the paverâs augers became entangled with the dowel assembly. The contractor removed the entire affected area (dowel assembly and concrete) and repaired the area. Also did not seal longitudinal joints. Pumping became evident and joints were sealed in 1997. 080200 CO Site is half new alignment and half reconstruction. Some sections cut, some fill. Material testing showed subgrade to be fine grained for some sections and coarse for others. One low-volume interchange near beginning of test sections. Subgrade was very wet during construction. Significant pumping [?] was evident prior to LCB placement on most sections. Much of PATB3 was contaminated with fines in the mixture. Appeared to drain, however. Different coarse aggregates were used for the 550 and 900 psi concretes. One-year PCC strength values do not exhibit the differences as placed. Final strengths are much closer together. 100200 DE Eight of the twelve sections contained partial shallow cuts but the cut subgrades had to meet type âAâ borrow specifications. Those cut subgrades that did not mee the type âAâ specifications were excavated to receive 12 inches of type âAâ borrow (with prior approval). A transverse construction joint was placed in section 102012. In sections 100203, 100207, and 100211, the longitudinal joint was sawn 5 days after the concrete placement. Bases did not extend the full width of the shoulder (with prior approval). Neoprene was used in the transverse joints (hot pour in three sections where the joints were rough) and hot-poured rubberized asphalt in the longitudinal joint. No joint sealant was used between the mainline concrete pavement and the asphalt shoulder. Joint sealing was done in 1996 and in the second construction season. The road was opened to construction traffic before joint sealing. In sections 100209, 100210, 100211, and 100212, edge drains were not located at the outside edges of the shoulder. Edge drain outlets were spaced at distances greater than 250 feet. In sections 100201, 100205, and 100209, âchecksâ [cracks?] within test sections were repaired by removing and replacing the concrete â all repairs full width. [Six repairs listed in 100201, seventeen repairs listed in 100205, and three repairs listed in 100209. 550 flexural strength concrete not used on sections 100202, 100203, and 100211 â 3000 psi compressive strength concrete used instead. 550 flexural strength concrete used on sections 100201, 100205, and 100209 â concrete removed and replaced with 650 flexural strength concrete. Sections 100202 and 100206 were placed with 900 psi flexural strength 61â2 bag mix. Concrete was later removed and replace with 900 psi flexural strength 71â2 bag mix. In section 100205, profile index is greater than 10 inches per mile (24.9). Note this section is scheduled for diamond grinding. TABLE 30 SPS-2 construction problems and deviations at sites with information available (continues on next page)
North Carolina, and North Dakota sites, no mention of these installations is made in the construction deviation reports. Construction deviation reports are not available for the California, Ohio, and Michigan sites, among others. ⢠A few instances of test sections that should be drained (test sections numbered 0209 through 0212 or 0221 through 0224, depending on the site), but at which no lateral outlets within or near the sections were found or marked for inspection. These instances are indicated by an ânâ rather than a âyâ in some cells in the last four test section columns in Table 31. These discrepancies were reported to LTPP in an LTPP Data Analysis/Operations Feedback Report (KTH-3, 11 June 34 2002) submitted by the NCHRP 1-34C research team. The responses were received from the LTPP regional support centers are summarized below. SPS-2 test sections designed to be undrained, but drains were found and inspected: ⢠Arkansas 0216 and 0218âThe extra outlets in Arkansas SPS-2 could have been put in to ensure that the adjacent or nearby laterals are functional. These extra laterals are full of silt and gravel and inspection was unable to pass beyond 2 to 5 ft. They can also be old lateral not removed during construction. ⢠California 0204âThis section has a nearby ramp, which necessitated the placement of the edge drain outlets (the section itself does not have a drainage layer). SHRP ID State Problem or Deviation 320200 NV The natural subgrade was lime treated 1 foot deep and then convered with the embankment layer. The LCB in section 320205 showed extensive shrinkage cracking throughout just prior to PCC paving. The LCB in sections 320207 and 320208 showed random block cracking every 15 to 20 ft within 16 ft of the inner edge. The 550 psi and 900 psi design strengths were changed to 375 psi and 750 psi due to materials constraints. During paving of section 320203, the concrete in front of the paver was watered frequently by hand and by truck. From section 320211 to the end of paving, the 3â4â aggregate was lowered 2% and the fine aggregate raised 2% from prior PCC paving. In section 320205, the transverse tie bars were pounded in by hand for the first 300 ft of the section. 200 feet into section 320205, the water reducer was increased to a maximum 4 percent. 300 feet into seciton 320205, the water/cement reatio was increased from 0.49 to 0.53. During paving of the second half of section 320206, the PCC in front of the DBI was watered down constantly. During paving of sections 320208, 320210, and 320211, the PCC in front of the DBI was sprayed periodically with water. Tie bars in the last 300 ft of section 320209 were pounded in by hand. Prior to paving section 320209, the PATB sagged slightly where the outlet trenches were placed, and was especially bad at station 1622+92. The PCC and PATB in section 320212 was torn out and replaced with 5â of CTB and 10.5â of NDOT PCC. Tie bars were inserted at both the centerline and lane/shoulder joints. Sections 320101, 320202, 320203, 320204, 320205, 320206, 320208, and 320210 had at least 10 meters of combined transverse and longitudinal cracking 8 months following paving, with sections 320202, 320203, 320205, and 320206 having greater than 100 meters of combined cracking. Two-way traffic during first three months. TABLE 30 (Continued)
⢠Michigan 0213 and 0220âDesign plans show no outlets planned for these sections. No as-built records are avail- able to confirm whether or not these outlets are present. ⢠North Carolina 0205âNo edgedrains were installed. The actual station of the outlets should be checked. Is the outlet inspected an actual edgedrain outlet or boxed culvert outlet? [Note: according to the video inspection report, the inspected outlet is a 102-mm (4-inch) diam- eter PVC pipe.] ⢠Ohio 0201, 0202, 0203, 0204, 0205, 0206, 0207, and 0208âDesign plans show no outlets planned for these sections. No as-built records are available to confirm whether or not these outlets are present. [Note: the video inspection reports indicate that these outlets are present but apparently capped internally.] SPS-2 test sections designed to be drained, but drains were not found: 35 ⢠Iowa 0223 and 0224âDesign plans show three outlets planned for section 190223 and four outlets planned for section190224. No as-built records are available to con- firm whether or not these outlets are present. ⢠Michigan 0222âDesign plans show one outlet planned for section 260222. Design plans include a note that the outlet spacing is less than 250 ft. No as-built records are available to confirm whether or not this outlet is present. ⢠Nevada 0212âThis section failed during construction and was released from the program (from an analysisâ and the LTPPâperspective, the section never existed). ⢠Wisconsin 0221, 0222, 0223, 0224âDesign plans show four outlets planned for section 550221, three for 550222, and two each for 550223 and 550224. No as-built records are available to confirm whether or not this outlet is pres- ent. [Note: the video inspection contractor reported that LTPP regional center support personnel visited the Wis- consin SPS2 site and could not locate any lateral outlets SHRP ID State Problem or Deviation 370200 NC Sections 370201, 370208, 370209, and 370212 contained both cut and fill. Sections 370203, 370205, 370208, 370211, and 370212 were located on curves instead of the preferred tangents. The add-on lane for monitoring and evaluating the performance of the six 8-inch PCC test sections has a different pavement structure than the adjacent mainline pavement. This add- on lane received prior approval. Section 370204 was separated from the others (with prior approval) by the Highway 64 interchange. In sections 370211 and 370212, prime that had been placed on the dense-graded aggregate base was opened to construction traffic for several weeks prior to placing the permeable asphalt-treated base. It was not an effective drainage layer. In sections 370209 and 270210, no prime was placed on the dense-graded âasphaltâ [aggregate?] base prior to placing the permeable asphalt-treated base layer. In sections 370209 and 370210, 5 inches of permeable asphalt-treated base were placed instead of the specified 4 inches, for construction reasons. In section 370204, a construction joint was placed at station 137+75 due to darkness. In section 370205, contraction cracks at station 307+30 and 308+24 were repaired by removing and replacing the concrete slab. In the 8-inch PCC sections, dowels were 1 inch diameter instead of 1.25 inches. The base layers beneath all test sections were not constructed to the full width of the inside and outside shoulders. In sections 370201, 370202, 370203, 370204, 370209, 370310, 370211, and 370212, the base extends for 2 ft beyond the edge of the pavement. In sections 370207 and 370208, the base was placed to the same width as the PCC. In section 370206, 370205, the base extends 2 ft beyond the outside edge of the pavement. Filter fabric was exposed for up to 4 months. Any noted deteriorated fabric was covered with filter fabric patches. The fly ash used to counteract high alkali content exceeded 15% by weight of cement. Water spray was used to soften the concrete when it piled up ahead of the finisher. TABLE 30 (Continued) (continues on next page)
to mark on either occasion. However, Wisconsin DOT personnel, and a research team member who visited the site, confirm that the outlets are present.] Test sections designed to be drained but for which drain- age outlets could not be located were not used in this analy- sis of the effects of drainage on pavement performance. Sim- ilarly, test sections designed to be undrained but at which lateral outlets were found and inspected also were not used in the analysis presented in this report. After reviewing the forms summarizing the video inspec- tions of the drainage installations, the 1-34C research team made a subjective assessment of whether the quality of drain- age functioning in each test section was âgoodâ or âpoor.â The ratings assigned are summarized in Table 32. Conditions that garnered a âpoorâ rating included lateral outlets being buried or fully blocked with silt, gravel, or other debris; longi- tudinal drains being fully blocked; or a considerable amount of water standing in longitudinal drains and not flowing out. Longitudinal drains and lateral outlets in a pavement struc- ture that has been in service some years are never pristine; there is nearly always some silt accumulation and some rodents and their nests. Whether or not there is enough mater- ial present to block the flow of water in the event of a stormâ 36 or whether the flow of water caused by a storm would clear out some or all of this materialâremains a matter of judg- ment until someone investigates this by conducting video inspections before and after storms. In general, if the amount of material described as being present did not seem sufficient to block the flow of water, a âgoodâ rating was assigned. In Table 32, a question mark alone in a cell indicates that no rating can be assigned because no laterals were inspected within the test section. A question mark with an asterisk indi- cates that a lateral was found and inspected visually, but the video camera could not be inserted in the lateral to inspect the interior of the longitudinal drain. In some cases this was because the inner diameter of the lateral was too small. In other cases this was because rodent screens were placed too far up in the lateral, out of armâs reach, and could not be removed so that the camera could pass. In the case of the Ohio SPS-2 sections 0201 through 0208, it appears to be due to the laterals being capped internally. EFFECTS OF DRAINAGE ON SPS-2 CONCRETE PAVEMENT PERFORMANCE Tables 24 and 25 show that the following specific test section comparisons may be conducted to assess the effects SHRP ID State Problem or Deviation 530200 WA Section 530203 located on cut section. Remaining sections subexcavated and filled. All sections except 530202 and 530203 had a rock fill placed prior to placing fill material. Sections 530201, 530206, and 530210 had rock fill only in parts of the section. The cylinders and cores from section 530207 yielded 14- and 28-day compressive strengths up to 2.5 times higher than the other LCB sections. The 14-day LCB cylinder compressive strengths for sections 530205 and 530206 were close to 300 psi; design called for 500 to 750 psi at 7 days. (Cores at 14 days for both these sections were within specifications.) Sections 530209 and 530212 had some patching done on the fabric in the edge drains and some soil contamination occurred. Soil was accidentally placed on the PATB inner shoulder in sections 530209 and 530212, then air blown off. Some contamination of the PATB occurred. The first 300 ft of PCC in section 530207 had 47 oz/yd3 of water reducer while the last 200 ft had 28 oz/yd3. Surface voids were visible in the last 200 ft. Section 530203 had a PCC water/cement ratio of 0.433 in the first 250 ft and 0.450 in the last 250 ft. The inner edge slumped significantly in a few locations. The slump at station 2+50 was 2.8 inches. Section 530206 had shrinkage cracks throughout the section following pages with crack widths between 1â2 and 1 mm. Static modulus of elasticity cores from each section had to be redrilled and retested. Cores were tested 10 weeks after scheduled 28-day testing. 1 Portland cement concrete 2 Lean concrete base. 3 Permeable asphalt-treated base. TABLE 30 (Continued)
of drainage on pavement performance in the SPS-2 experi- ment, holding concrete slab thickness, strength, and width constant: (A) Undrained dense-graded aggregate (AGG) versus permeable asphalt-treated base (PATB): ⢠0201 versus 0209: 8-inch slab, 12 feet wide, 550 psi concrete ⢠0202 versus 0210: 8-inch slab, 14 feet wide, 900 psi concrete ⢠0203 versus 0211: 11-inch slab, 14 feet wide, 550 psi concrete ⢠0204 versus 0212: 11-inch slab, 12 feet wide, 900 psi concrete ⢠0213 versus 0221: 8-inch slab, 14 feet wide, 550 psi concrete ⢠0214 versus 0222: 8-inch slab, 12 feet wide, 900 psi concrete ⢠0215 versus 0223: 11-inch slab, 12 feet wide, 550 psi concrete ⢠0216 versus 0224: 11-inch slab, 14 feet wide, 900 psi concrete 37 (B) Undrained lean concrete base (LCB) versus perme- able asphalt-treated base (PATB): ⢠0205 versus 0209: 8-inch slab, 12 feet wide, 550 psi concrete ⢠0206 versus 0210: 8-inch slab, 14 feet wide, 900 psi concrete ⢠0207 versus 0211: 11-inch slab, 14 feet wide, 550 psi concrete ⢠0208 versus 0212: 11-inch slab, 12 feet wide, 900 psi concrete ⢠0217 versus 0221: 8-inch slab, 14 feet wide, 550 psi concrete ⢠0218 versus 0222: 8-inch slab, 12 feet wide, 900 psi concrete ⢠0219 versus 0223: 11-inch slab, 12 feet wide, 550 psi concrete ⢠0220 versus 0224: 11-inch slab, 14 feet wide, 900 psi concrete The sites with test sections useful to each of the above comparisons were identified by combining the information about which test sections had drainage inspected (Table 31) Test Section ID 0201 and 0213 0202 and 0214 0203 and 0215 0204 and 0216 0205 and 0217 0206 and 0218 0207 and 0219 0208 and 0220 0209 and 0221 0210 and 0222 0211 and 0223 0212 and 0224 Base Type Dense-graded aggregate Lean concrete base Permeable asphalt-treated base over aggregate State Undrained Drained AZ y1 y y y AR y2 y y y y y CA y y y y y CO y y y y DE y y y y IA y y n3 n KS y y y y MI y y y n y y NV y y y n NC y y y y y ND y y y y OH y y y y y y y y y y y y WA y y y y WI n n n n 1 y = in unshaded cells, subdrains found and inspected 2 y = in shaded cells, drains found and inspected, even though according to the experiment design the section should not have drains. 3 n = subdrains not found or found but not inspected. TABLE 31 SPS-2 test-section sections with drainage outlets inspected with video
with the information about the subjective ratings of drainage functioning (Table 32). For each of the two sets of comparisons listed, and for each pavement performance indicator considered (IRI, trans- verse cracking, and longitudinal cracking), paired t-tests were conducted to determine whether or not the mean dif- ference between the undrained and drained test section pairs was significant. (Due to irregularities in the available fault- ing data, as discussed more later, statistical analyses of fault- ing were not conducted.) Three paired t-tests were conducted each time: ⢠For the subset of test section pairs with drainage func- tioning rated as good (denoted by G in the column âDrainage functioningâ in Tables 33 through 38), ⢠For the subset of test section pairs rated as poor (denoted by P in the column âDrainage functioningâ in Tables 33 through 38), and ⢠For all valid test section pairs regardless of drainage func- tioning (denoted by G, P, or ? in Tables 33 through 38). The test section pairs excluded from these comparisons were: 38 ⢠Those that had subdrainage outlets located and inspected in the section that was designed to be undrained (denoted by X in Tables 33 through 38), and ⢠Those lacking measurement data for one or both of the test sections (denoted by --- in Tables 33 through 38). The difference in the performance measures (IRI, trans- verse cracking, or longitudinal cracking) for each test section pair is calculated as the measured value for the undrained section minus the measured value for the drained section. Thus, a positive difference indicates that the measured value was greater in the undrained section, and a negative difference indicates that the measured value was greater in the drained section. The mean difference for all the pairs considered is the sum of the pairwise differences divided by the number of pairs. Whether or not the mean difference is significant (at a selected significance level, e.g., 95 percent) is determined by calcu- lating the lower and upper limits of (95-percent) confidence interval around the mean difference. If zero is not contained within the lower and upper limits of the confidence interval, the mean difference can be concluded, with 95 percent con- fidence, to be significantly different than zero. Test Section ID 0201 and 0213 0202 and 0214 0203 and 0215 0204 and 0216 0205 and 0217 0206 and 0218 0207 and 0219 0208 and 0220 0209 and 0221 0210 and 0222 0211 and 0223 0212 and 0224 Base Type Dense-graded aggregate Lean concrete base Permeable asphalt-treated base over aggregate State Undrained Drained AZ G1 G G G AR P2 P P P P P CA P G G G P CO G P P P DE P G P G IA P P ? ? KS G G G G MI P P P ? P P NV G G G ? NC P P P P P ND G G G G OH ?*3 ?* ?* ?* ?* ?* ?* ?* G P G P WA G G G G WI ? ? ? ? 1 G = Drainage function rated as good. 2 P = Drainage function rated as poor. 3 ?* = Camera could not be inserted. TABLE 32 Subjective ratings of drainage functioning at SPS-1 test sections based on video inspection results
Effect of Drainage on Concrete Pavement Roughness (IRI) Development For each SPS-2 site, IRI data were extracted from the MON_PROFILE_MASTER table in the LTPP database. An IRI for each run was calculated as the average of the runâs left and right wheelpath IRIs. An average IRI for each test- ing date was then calculated as the average of the run IRIs for that dateâmost often five runs, but sometimes as few as one or as many as fifteen. The expectation is that IRI will tend to increase over time, as the pavement deteriorates. However, IRI does not always increase steadily over time. Sometimes the IRI of a test sec- tion is lower than the IRI measured on the same test section a year earlier, a month earlier, or even a day earlier. Physical reasons why IRI might decrease from one testing date to the next include the following (from Reference 4): ⢠Rehabilitation or maintenance between testing dates; ⢠Seasonal variation; ⢠Measurement in different paths; ⢠Different starting locations; ⢠Spikes in the data caused by reflection of light from the white paint stripe at the start of a test section; or ⢠Problems with the profilometer electronics, sensors, or distance measurement. However, it is not necessarily true that an IRI decrease, or an IRI increase for that matter, always has a physical explana- tion. Some portion of the variation seen in IRI data is random variation. That is, some fluctuations in IRI, both upward and downward, are not significantly different than no change at all. The first available IRI is not necessarily the IRI immedi- ately after opening to traffic. The first testing date for which IRI data are available for all or most of the test sections at a site may be a year or more after the opening date. (Note that the date of opening to traffic is shown for each site in the ESAL calculation summary in Appendix B.) Similarly, the latest IRI measurements used in the analysis are not neces- sarily those for the latest IRI measurement date at any one test section at a site, but rather those for the latest IRI mea- surement date for which measurements are available for most or all of the sections at a site. The IRI histories of the test sec- tions at each SPS-2 site are shown in Appendix B. The comparisons of IRI change between drained and undrained sections of matching designs are shown in Tables 33 and 34. Which comparisons were deemed possible was assessed on the basis of the drainage detection and drainage functioning information summarized in Tables 31 and 32. Table 33 shows the comparisons of undrained aggregate base (AGG) versus permeable asphalt-treated base (PATB). The change in IRI was slightly greater (as indicated by a pos- itive mean difference in change in IRI) in the undrained AGG sections than in the drained PATB sections of otherwise like design. This difference was found to be statistically signifi- 39 cant when all drained sections were considered together, but not when sections with drainage functioning subjectively rated as good were separated from those with drainage functioning rated as poor. The mean difference in IRI change was slightly greater for sections with poor drainage functioning than for sections with good drainage functioning. Thisâto the extent that the subjective ratings of drainage functioning are accu- rateâsuggests that quality of drainage is not a significant fac- tor in the differences observed. Table 34 shows the comparisons of undrained lean concrete base (LCB) versus permeable asphalt-treated base (PATB). The change in IRI was slightly greater in the undrained LCB sections than in the drained PATB sections, but the differences were not found to be significant in any of the cases considered (good drainage functioning, poor drainage functioning, or the two combined). Again, the mean difference in IRI change between undrained and drained sections was greater for PATB sections with poor drainage functioning than PATB sections with good drainage functioning, which tends to discount qual- ity of drainage as a significant factor. Effect of Drainage on Concrete Pavement Faulting Development The faulting histories of the SPS-2 sites are shown in Appendix B. The estimated accumulated ESALs correspond- ing to the most recent faulting measurements are reported in Appendix B. The accumulated ESAL values are slightly dif- ferent than those reported earlier for the IRI histories, since faulting and IRI were measured on different dates. The faulting histories for the SPS-2 sites do not demon- strate the more or less consistently increasing trend with time that is normally expected. The average faulting for the dif- ferent test sections increases and decreases erratically from measurement date to measurement date; and, in some cases, the average faulting changes from positive to negative to pos- itive again. This may be due to the very small magnitudes of faulting measured: a lot of small-negative measurements, zero measurements, and small-positive measurements may result in erratic average values. When larger magnitudes of faulting developâsuch that the averages are consistently being cal- culated from positive measurementsâtrends in faulting with time and traffic may become more evident. Effect of Drainage on Concrete Pavement Cracking Development Data for three types of cracking in SPS-2 pavements were extracted from the LTPP database: ⢠Corner breaks; ⢠Transverse cracking (all severities, sealed and unsealed); and ⢠Longitudinal cracking (all severities, sealed and unsealed).
IRI Difference in IRI AGG PATB Age, years Drainage function- ing All Good Poor Site 0201 0209 CA 06 ---1 --- --- --- DE 10 0.355 0.061 3.19 P2 0.294 0.294 KS 20 0.538 0.006 8.17 G3 0.532 0.532 NV 32 1.172 0.192 3.97 G 0.980 0.980 NC 37 0.214 0.046 4.04 P 0.168 0.168 OH 39 0.205 0.093 4.01 X4 WA 53 0.142 0.106 4.61 G 0.036 0.036 Site 0202 0210 CA 06 --- --- --- --- DE 10 0.122 0.072 3.19 G 0.050 0.050 KS 20 -0.013 0.060 8.17 G -0.073 -0.073 NV 32 0.621 0.096 0.82 G 0.525 0.525 NC 37 0.050 0.110 4.04 P -0.060 -0.060 OH 39 0.248 0.089 4.01 X WA 53 0.027 0.239 4.61 G -0.212 -0.212 Site 0203 0211 CA 06 --- --- --- --- DE 10 -0.042 0.033 3.19 P -0.075 -0.075 KS 20 0.007 0.094 8.17 G -0.087 -0.087 NV 32 0.205 0.311 3.97 G -0.106 -0.106 NC 37 0.116 -0.024 4.04 P 0.140 0.140 OH 39 -0.067 -0.034 4.01 X WA 53 0.061 -0.023 4.61 G 0.084 0.084 Site 0204 0212 CA 06 --- --- --- --- DE 10 0.073 0.050 3.19 G 0.023 0.023 KS 20 -0.167 -0.023 8.17 G -0.144 -0.144 NV 32 0.420 0.288 3.97 ?5 0.132 NC 37 0.121 0.002 4.04 P 0.119 0.119 OH 39 -0.008 -0.079 4.01 X WA 53 0.031 0.127 4.61 G -0.096 -0.096 Site 0213 0221 AZ 04 0.301 0.064 6.86 G 0.237 0.237 AR 05 0.362 0.075 3.78 P 0.287 0.287 CO 08 -0.010 -0.065 6.33 G 0.055 0.055 IA 19 -0.110 0.170 5.26 P -0.280 -0.280 MI 26 1.151 0.074 4.60 X ND 38 -0.025 -0.065 2.07 G 0.040 0.040 WI 55 0.469 0.239 2.40 ? 0.230 Site 0214 0222 AZ 04 -0.122 -0.076 6.86 G -0.046 -0.046 AR 05 0.585 -0.064 3.78 P 0.649 0.649 CO 08 -0.088 0.012 6.33 P -0.100 -0.100 IA 19 0.080 -0.040 5.26 P 0.120 0.120 MI 26 0.216 -0.068 4.60 ? 0.284 ND 38 -0.067 -0.070 2.07 G 0.003 0.003 WI 55 0.316 0.150 1.58 ? 0.166 Site 0215 0223 AZ 04 0.341 0.165 6.86 G 0.176 0.176 AR 05 0.224 0.106 3.78 P 0.118 0.118 CO 08 0.075 -0.123 6.33 P 0.198 0.198 IA 19 0.034 -0.155 5.26 ? 0.189 MI 26 0.733 -0.017 4.60 P 0.750 0.750 ND 38 0.051 -0.067 2.07 G 0.118 0.118 WI 55 0.144 0.187 2.40 ? -0.043 Site 0216 0224 AZ 04 -0.052 0.088 6.86 G -0.140 -0.140 AR 05 0.549 0.042 3.78 X CO 08 -0.001 -0.036 6.33 P 0.035 0.035 IA 19 -0.013 -0.063 5.26 ? 0.050 MI 26 -0.120 -0.079 4.60 P -0.041 -0.041 ND 38 0.031 -0.053 2.07 G 0.084 0.084 WI 55 0.139 0.204 2.40 ? -0.065 Mean difference 0.115 0.093 0.145 N 46 22 16 SD 0.248 0.274 0.264 t alpha/2, n-1 2.481 2.595 2.687 Confidence interval lower limit 0.025 -0.059 -0.032 Confidence interval upper limit 0.206 0.244 0.322 Significant difference (Overall confidence level = 95%) yes no no 1 --- = lacking measurement data for one or both test sections. 2 P = Drainage function rated as poor. 3 G = Drainage function rated as good. 4 X = Subdrainage outlets located and inspected in the section that was designed to be undrained. 5 ? = Drainage outlets not found. TABLE 33 Change in International Roughness Index (IRI) in SPS-1 undrained dense-graded aggregate (AGG) base sections versus drained permeable asphalt-treated base (PATB) sections
IRI Difference in IRI LCB PATB Age, years Drainage functioning All Good Poor Site 0205 0209 CA 06 ---1 --- --- --- DE 10 0.144 0.061 3.19 P2 0.083 0.083 KS 20 0.177 0.006 8.17 G3 0.171 0.171 NV 32 0.298 0.192 3.97 G 0.106 0.106 NC 37 0.156 0.046 4.04 X4 OH 39 0.123 0.093 4.01 X WA 53 0.019 0.106 4.61 G -0.087 -0.087 Site 0206 0210 CA 06 --- --- --- --- DE 10 0.124 0.072 3.19 G 0.052 0.052 KS 20 0.070 0.060 8.17 G 0.010 0.010 NV 32 0.122 0.096 0.82 G 0.026 0.026 NC 37 0.038 0.110 4.04 P -0.072 -0.072 OH 39 0.180 0.089 4.01 X WA 53 1.005 0.239 4.61 G 0.766 0.766 Site 0207 0211 CA 06 --- --- --- --- DE 10 0.029 0.033 3.19 P -0.004 -0.004 KS 20 0.097 0.094 8.17 G 0.003 0.003 NV 32 0.222 0.311 3.97 G -0.089 -0.089 NC 37 0.036 -0.024 4.04 P 0.060 0.060 OH 39 0.060 -0.034 4.01 X WA 53 0.134 -0.023 4.61 G 0.157 0.157 Site 0208 0212 CA 06 --- --- --- --- DE 10 0.013 0.050 3.19 G -0.037 -0.037 KS 20 0.084 -0.023 8.17 G 0.107 0.107 NV 32 0.013 0.288 3.97 ?5 -0.275 NC 37 -0.032 0.002 4.04 P -0.034 -0.034 OH 39 -0.045 -0.079 4.01 X WA 53 0.364 0.127 4.61 G 0.237 0.237 Site 0217 0221 AZ 04 -0.110 0.064 6.86 G -0.174 -0.174 AR 05 0.133 0.075 3.78 P 0.058 0.058 CO 08 0.098 -0.065 6.33 G 0.163 0.163 IA 19 0.363 0.170 5.26 P 0.193 0.193 MI 26 2.149 0.074 4.60 P 2.075 2.075 ND 38 0.105 -0.065 2.07 G 0.170 0.170 WI 55 0.043 0.239 2.40 ? -0.196 Site 0218 0222 AZ 04 -0.355 -0.076 6.86 G -0.279 -0.279 AR 05 0.042 -0.064 3.78 X CO 08 -0.073 0.012 6.33 P -0.085 -0.085 IA 19 0.054 -0.040 5.26 P 0.094 0.094 MI 26 0.358 -0.068 4.60 ? 0.426 ND 38 -0.026 -0.070 2.07 G 0.044 0.044 WI 55 -0.103 0.134 2.40 ? -0.237 TABLE 34 Change in International Roughness Index (IRI) in SPS-2 undrained lean concrete base (LCB) sections versus drained permeable asphalt treated base (PATB) sections (continues on next page)
There were very few SPS-2 pavement sections with cor- ner breaks, and there were almost never more than one or two corner breaks in the test section. Thus, the number of corner breaks in each section where they occurred was multiplied by 2 meters, and added to the total length of transverse cracking in meters. Separately, the total length of longitudinal crack- ing was determined for each pavement section. Because of the large proportion of test sections that still have no transverse and/or longitudinal cracking, the cracking histories of the SPS-2 sites are not shown in Appendix B. However, a statistical examination of the most recently noted levels of transverse and longitudinal cracking is possible. The comparisons of transverse cracking between drained and undrained sections of matching designs are shown in Tables 35 and 36. Which comparisons were deemed possible was assessed on the basis of the drainage detection and drain- age functioning information summarized in Tables 31 and 32. It should be noted an unusually large amount of cracking has occurred in several sections at the Nevada SPS-2 site, which had a great many problems with slab cracking during and soon after construction. Table 35 shows the comparisons of undrained aggregate base (AGG) versus permeable asphalt-treated base (PATB). Transverse cracking was slightly greater (as indicated by a positive mean difference) in the undrained AGG sections 42 than in the drained PATB sections of otherwise like design. The difference was not, however, found to be statistically sig- nificant for sections with good drainage functioning, poor drainage functioning, or the two groups considered together. The mean difference in transverse cracking was greater for sections with good drainage functioning than sections with poor drainage functioning, which suggests that quality of drainage may play a role in the slight differences observed. Table 36 shows the comparisons of undrained lean concrete base (LCB) versus permeable asphalt-treated base (PATB). Transverse cracking was slightly greater in the undrained LCB sections than in the drained PATB sections, but the differences were not found to be significant in any of the cases considered (good drainage functioning, poor drainage functioning, or the two combined). Again, the mean difference in transverse cracking was greater for sections with good drainage func- tioning than sections with poor drainage functioning, which suggests that quality of drainage may play a role in the slight differences observed. The comparisons of longitudinal cracking are presented in Tables 37 and 38. Which comparisons were deemed possible was assessed on the basis of the drainage detection and drain- age functioning information summarized in Tables 31 and 32. It should be again noted that an unusually large amount of cracking has occurred in several sections at the Nevada Site 0219 0223 AZ 04 0.096 0.165 6.86 G -0.069 -0.069 AR 05 0.121 0.106 3.78 P 0.015 0.015 CO 08 0.070 -0.123 6.33 P 0.193 0.193 IA 19 -0.068 -0.155 5.26 ? 0.087 MI 26 0.178 -0.017 4.60 P 0.195 0.195 ND 38 0.053 -0.067 2.07 G 0.120 0.120 WI 55 0.236 0.187 2.40 ? 0.049 Site 0220 0224 AZ 04 -0.094 0.088 6.86 G -0.182 -0.182 AR 05 0.319 0.042 3.78 P 0.277 0.277 CO 08 0.132 -0.036 6.33 P 0.168 0.168 IA 19 0.030 -0.063 5.26 ? 0.093 MI 26 0.024 -0.079 4.60 X ND 38 0.123 -0.053 2.07 G 0.176 0.176 WI 55 0.065 0.204 2.40 ? -0.139 Mean difference 0.098 0.063 0.214 N 45 22 15 SD 0.354 0.207 0.526 t alpha/2, n-1 2.483 2.595 2.711 Confidence interval lower limit -0.033 -0.051 -0.154 Confidence interval upper limit 0.229 0.178 0.582 Significant difference (Overall confidence level = 95%) no no no 1 --- = lacking measurement data for one or both test sections. 2 P = Drainage function rated as poor. 3 G = Drainage function rated as good. 4 X = Subdrainage outlets located and inspected in the section that was designed to be undrained. 5 ? = Drainage outlets not found. TABLE 34 (Continued)
Base Type AGG PATB Difference Drained N Y Age, years Drainage functioning All Good Poor CA 06 ---1 --- --- --- DE 10 0 0 4.11 P2 0 0 KS 20 3 0 4.82 G3 3 3 NV 32 85 1 5.64 G 84 84 NC 37 0 0 6.26 P 0 0 OH 39 0 0 4.51 X4 WA 53 0 0 4.52 G 0 0 CA 06 --- --- --- --- DE 10 0 0 4.11 G 0 0 KS 20 1 0 4.82 G 1 1 NV 32 153 58 1.75 G 95 95 NC 37 0 0 6.26 P 0 0 OH 39 6 0 4.51 X WA 53 0 0 4.52 G 0 0 CA 06 --- --- --- --- DE 10 0 0 4.11 P 0 0 KS 20 0 0 4.82 G 0 0 NV 32 423 11 5.64 G 412 412 NC 37 0 0 6.26 P 0 0 OH 39 0 0 4.51 X WA 53 0 0 4.52 G 0 0 CA 06 --- --- --- --- DE 10 0 0 4.11 G 0 0 KS 20 0 0 4.82 G 0 0 NV 32 42 --- 5.64 --- NC 37 0 0 6.26 P 0 0 OH 39 4 0 4.51 X WA 53 0 0 4.52 G 0 0 AZ 04 0 0 6.45 G 0 0 AR 05 2 0 4.66 P 2 2 CO 08 0 0 6.55 G 0 0 IA 19 0 0 5.19 P 0 0 MI 26 13 0 5.01 X ND 38 0 0 5.71 G 0 0 WI 55 --- --- --- --- AZ 04 0 0 6.45 G 0 0 AR 05 0 0 4.66 P 0 0 CO 08 0 0 6.55 P 0 0 IA 19 0 0 5.19 P 0 0 MI 26 0 0 5.96 ?5 0 ND 38 0 0 5.71 G 0 0 WI 55 --- --- --- --- Site 0215 0223 AZ 04 0 0 6.45 G 0 0 AR 05 0 0 4.66 P 0 0 CO 08 0 0 6.55 P 0 0 IA 19 0 0 5.19 ? 0 MI 26 7 0 5.96 P 7 7 ND 38 0 0 5.71 G 0 0 WI 55 --- --- --- --- Site 0216 0224 AZ 04 0 0 6.45 G 0 0 AR 05 0 2 4.66 X CO 08 0 0 6.55 P 0 0 IA 19 0 0 5.19 ? 0 MI 26 0 0 5.96 P 0 0 ND 38 0 0 5.71 G 0 0 WI 55 --- --- --- --- Mean difference 14.7 27.0 0.6 n 41 22 16 SD 66.5 89.9 1.8 t alpha/2, n-1 2.493 2.595 2.687 Confidence interval lower limit -11.2 -22.7 -0.6 Confidence interval upper limit 40.6 76.8 1.8 Significant difference (Overall confidence level = 95%) no no no 1 --- = lacking measurement data for one or both test sections. 2 P = Drainage function rated as poor. 3 G = Drainage function rated as good. 4 X = Subdrainage outlets located and inspected in the section that was designed to be undrained. Site Site Site Site Site Site 0201 0202 0203 0204 0213 0214 0222 0221 0212 0211 0210 0209 TABLE 35 Transverse cracking in meters in SPS-2 undrained dense-graded aggregate (AGG) sections versus drained permeable asphalt-treated base (PATB) sections
Base Type LCB PATB Difference Drained N Y Age, years Drainage functioning All Good Poor Site 0205 0209 CA 06 ---1 --- --- --- DE 10 29 0 4.11 P2 29 29 KS 20 0 0 7.33 G3 0 0 NV 32 234 1 5.64 G 233 233 NC 37 6 0 6.26 X4 OH 39 26 0 4.51 X WA 53 1 0 4.52 G 1 1 Site 0206 0210 CA 06 --- --- --- --- DE 10 0 0 4.11 G 0 0 KS 20 0 0 7.33 G 0 0 NV 32 253 58 1.75 G 195 195 NC 37 0 0 6.26 P 0 0 OH 39 0 0 2.94 X WA 53 10 0 4.52 G 10 10 Site 0207 0211 CA 06 --- --- --- --- DE 10 0 0 4.11 P 0 0 KS 20 0 0 7.33 G 0 0 NV 32 36 11 5.64 G 25 25 NC 37 0 0 6.26 P 0 0 OH 39 0 0 4.51 X WA 53 2 0 4.52 G 2 2 Site 0208 0212 CA 06 --- --- --- --- DE 10 0 0 4.11 G 0 0 KS 20 0 0 7.33 G 0 0 NV 32 118 --- 5.64 --- NC 37 0 0 6.26 P 0 0 OH 39 0 0 4.51 X WA 53 0 0 4.52 G 0 0 Site 0217 0221 AZ 04 12 0 6.45 G 12 12 AR 05 0 0 4.66 P 0 0 CO 08 0 0 6.55 G 0 0 IA 19 13 0 5.19 P 13 13 MI 26 0 0 3.56 P 0 0 ND 38 17 0 5.71 G 17 17 WI 55 --- --- --- --- Site 0218 0222 AZ 04 16 0 6.45 G 16 16 AR 05 37 0 4.66 X CO 08 4 0 6.55 P 4 4 IA 19 0 0 5.19 P 0 0 MI 26 44 0 1.59 ?5 44 ND 38 0 0 5.71 G 0 0 WI 55 --- --- --- --- Site 0219 0223 AZ 04 0 0 6.45 G 0 0 AR 05 0 0 4.66 P 0 0 CO 08 0 0 6.55 P 0 0 IA 19 0 0 5.19 ? 0 MI 26 0 0 5.96 P 0 0 ND 38 0 0 5.71 G 0 0 WI 55 --- --- --- --- Site 0220 0224 AZ 04 0 0 6.45 G 0 0 AR 05 0 2 4.66 P -2 -2 CO 08 2 0 6.55 P 2 2 IA 19 0 0 5.19 ? 0 MI 26 0 0 5.96 X ND 38 0 0 5.71 G 0 0 WI 55 --- --- --- --- Mean difference 15.0 23.2 3.1 N 40 22 15 SD 47.4 62.4 8.0 t alpha/2, n-1 2.496 2.595 2.711 Confidence interval lower limit -3.7 -11.3 -2.5 Confidence interval upper limit 33.7 57.8 8.7 Significant difference (Overall confidence level = 95%) no no no 1 --- = lacking measurement data for one or both test sections. 2 P = Drainage function rated as poor. 3 G = Drainage function rated as good. 4 X = Subdrainage outlets located and inspected in the section that was designed to be undrained. 5 ? = Drainage outlets not found. TABLE 36 Transverse cracking in meters in SPS-2 undrained lean concrete base (LCB) sections versus drained permeable asphalt-treated base (PATB) sections
Base Type AGG PATB Difference Drained N Y Age, years Drainage functioning All Good Poor Site 0201 0209 CA 06 ---1 --- --- --- DE 10 0 0 4.11 P2 0 0 KS 20 8 0 4.82 G53 8 8 NV 32 119 4 5.64 G 115 115 NC 37 0 0 6.26 P 0 0 OH 39 0 0 4.51 X4 WA 53 0 0 4.52 G 0 0 Site 0202 0210 CA 06 --- --- --- --- DE 10 0 0 4.11 G 0 0 KS 20 0 0 4.82 G 0 0 NV 32 339 12 1.75 G 327 327 NC 37 0 0 6.26 P 0 0 OH 39 0 0 4.51 X WA 53 0 0 4.52 G 0 0 Site 0203 0211 CA 06 --- --- --- --- DE 10 0 0 4.11 P 0 0 KS 20 0 0 4.82 G 0 0 NV 32 206 9 5.64 G 197 197 NC 37 0 0 6.26 P 0 0 OH 39 0 0 4.51 X WA 53 0 0 4.52 G 0 0 Site 0204 0212 CA 06 --- --- --- --- DE 10 0 0 4.11 G 0 0 KS 20 0 0 4.82 G 0 0 NV 32 0 --- 5.64 --- NC 37 0 0 6.26 P 0 0 OH 39 0 0 4.51 X WA 53 0 0 4.52 G 0 0 Site 0213 0221 AZ 04 8 3 6.45 G 5 5 AR 05 53 0 4.66 P 53 53 CO 08 0 3 6.55 G -3 -3 IA 19 0 0 5.19 P 0 0 MI 26 0 0 5.01 X ND 38 0 0 5.71 G 0 0 WI 55 --- --- --- --- Site 0214 0222 AZ 04 0 3 6.45 G -3 -3 AR 05 0 0 4.66 P 0 0 CO 08 0 1 6.55 P -1 -1 IA 19 0 7 5.19 P -7 -7 MI 26 0 0 5.96 ?5 0 ND 38 0 0 5.71 G 0 0 WI 55 --- --- --- --- Site 0215 0223 AZ 04 0 0 6.45 G 0 0 AR 05 0 0 4.66 P 0 0 CO 08 0 0 6.55 P 0 0 IA 19 0 0 5.19 ? 0 MI 26 0 0 5.96 P 0 0 ND 38 0 0 5.71 G 0 0 WI 55 --- --- --- --- Site 0216 0224 AZ 04 0 1 6.45 G -1 -1 AR 05 0 0 4.66 X CO 08 0 0 6.55 P 0 0 IA 19 0 5 5.19 ? -5 MI 26 0 0 5.96 P 0 0 ND 38 0 8 5.71 G -8 -8 WI 55 --- --- --- --- Mean difference 16.5 29.0 2.8 n 41 22 16 SD 61.4 81.9 13.5 t alpha/2, n-1 2.493 2.595 2.687 Confidence interval lower limit -7.4 -16.3 -6.3 Confidence interval upper limit 40.4 74.2 11.9 Significant difference (Overall confidence level = 95%) no no no 1 --- = lacking measurement data for one or both test sections. 2 P = Drainage function rated as poor. 3 G = Drainage function rated as good. 4 X = Subdrainage outlets located and inspected in the section that was designed to be undrained. 5 ? = Drainage outlets not found. TABLE 37 Longitudinal cracking in meters in SPS-2 undrained aggregate base (AGG) sections versus drained permeable asphalt-treated base (PATB) sections
Base Type LCB PATB Difference Drained N Y Age, years Drainage functioning All Good Poor Site 0205 0209 CA 06 ---1 --- --- --- DE 10 6 0 4.11 P2 6 6 KS 20 0 0 7.33 G3 0 0 NV 32 271 4 5.64 G 267 267 NC 37 1 0 6.26 X4 OH 39 0 0 4.51 X WA 53 0 0 4.52 G 0 0 Site 0206 0210 CA 06 --- --- --- --- DE 10 0 0 4.11 G 0 0 KS 20 2 0 7.33 G 2 2 NV 32 273 12 1.75 G 261 261 NC 37 0 0 6.26 P 0 0 OH 39 21 0 2.94 X WA 53 2 0 4.52 G 2 2 Site 0207 0211 CA 06 --- --- --- --- DE 10 45 0 4.11 P 45 45 KS 20 0 0 7.33 G 0 0 NV 32 35 9 5.64 G 26 26 NC 37 0 0 6.26 P 0 0 OH 39 0 0 4.51 X WA 53 0 0 4.52 G 0 0 Site 0208 0212 CA 06 --- --- --- --- DE 10 0 0 4.11 G 0 0 KS 20 0 0 7.33 G 0 0 NV 32 33 --- 5.64 --- NC 37 0 0 6.26 P 0 0 OH 39 0 0 4.51 X WA 53 0 0 4.52 G 0 0 Site 0217 0221 AZ 04 12 3 6.45 G 9 9 AR 05 50 0 4.66 P 50 50 CO 08 13 3 6.55 G 10 10 IA 19 0 0 5.19 P 0 0 MI 26 6 0 3.56 P 6 6 ND 38 43 0 5.71 G 43 43 WI 55 --- --- --- --- Site 0218 0222 AZ 04 15 3 6.45 G 12 12 AR 05 37 0 4.66 X CO 08 0 1 6.55 P -1 -1 IA 19 0 7 5.19 P -7 -7 MI 26 20 0 1.59 ?5 20 ND 38 4 0 5.71 G 4 4 WI 55 --- --- --- --- Site 0219 0223 AZ 04 0 0 6.45 G 0 0 AR 05 0 0 4.66 P 0 0 CO 08 0 0 6.55 P 0 0 IA 19 0 0 5.19 ? 0 MI 26 0 0 5.96 P 0 0 ND 38 0 0 5.71 G 0 0 WI 55 --- --- --- --- Site 0220 0224 AZ 04 0 1 6.45 G -1 -1 AR 05 0 0 4.66 P 0 0 CO 08 0 0 6.55 P 0 0 IA 19 0 5 5.19 ? -5 MI 26 0 0 5.96 X ND 38 0 8 5.71 G -8 -8 WI 55 --- --- --- --- Mean difference 18.5 28.5 6.6 N 40 22 15 SD 58.5 77.0 16.9 t alpha/2, n-1 2.496 2.595 2.711 Confidence interval lower limit -4.6 -14.1 -5.2 Confidence interval upper limit 41.6 71.1 18.4 Significant difference (Overall confidence level = 95%) no no no 1 --- = lacking measurement data for one or both test sections. 2 P = Drainage function rated as poor. 3 G = Drainage function rated as good. 4 X = Subdrainage outlets located and inspected in the section that was designed to be undrained. 5 ? = Drainage outlets not found. TABLE 38 Longitudinal cracking in meters in SPS-2 undrained lean concrete base (LCB) sections versus drained permeable asphalt-treated base (PATB) sections
SPS-2 site, which had a great many problems with slab crack- ing during and soon after construction. Table 37 shows the comparisons of undrained aggregate base (AGG) versus drained permeable asphalt-treated base (PATB). Longitudinal cracking was slightly greater (as indi- cated by a positive mean difference) in the undrained AGG sections than in the drained PATB sections of otherwise like design. The difference was not, however, found to be statis- tically significant for sections with good drainage function- ing, poor drainage functioning, or the two groups considered together. The mean difference in longitudinal cracking was greater for sections with good drainage functioning than sec- tions with poor drainage functioning, which suggests that 47 quality of drainage may play a role in the slight differences observed. Table 38 shows the comparisons of undrained lean concrete base (LCB) versus permeable asphalt-treated base (PATB). Longitudinal cracking was slightly greater in the undrained LCB sections than in the drained PATB sections, but the dif- ferences were not found to be significant in any of the cases considered (good drainage functioning, poor drainage func- tioning, or the two combined). Again, the mean difference in longitudinal cracking was greater for sections with good drain- age functioning than sections with poor drainage function- ing, which suggests that quality of drainage may play a role in the slight differences observed.
