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5 CHAPTER 2 STATE OF THE PRACTICE FOR EOT CONCRETE REPAIRS Full-depth repair is a commonly used concrete pavement gates are blended with portland cement, water, and admixtures restoration technique for restoring both structural integrity and to produce a stiff but moldable mass that hardens through a ride quality to concrete pavements suffering distresses listed in chemical process referred to as hydration. In the resulting Table 1 (FHWA 2003). By definition, full-depth repairs are stone-like mass, the aggregates have been bound together by made through the entire depth of the pavement slab, are almost the hydration products formed through chemical reactions always full width across the lane, and have minimum specified between the water and cement. Air is also entrapped and/or lengths dependent upon the design of the existing pavement. entrained, typically making up 5 to 7 percent of the total mix- After the repair boundaries are demarcated with full-depth saw ture volume. cuts and the deteriorated concrete is removed, the base is repaired, the load-transfer devices are installed, and new PCC is placed. EOT concrete is commonly used in situations where Aggregates lane closure must be kept to a minimum. Aggregates make up 70 to 80 percent of the total volume of There are a number of sources of information regarding hardened concrete (Folliard and Smith 2003). As such, they full-depth repair of concrete pavement, including publica- have a large impact on the behavior of the composite. Many tions by the Federal Highway Administration (FHWA 2003), characteristics and test methods are used to assess aggregates. the American Concrete Pavement Association (ACPA 1995), Folliard and Smith (2003) recommended essential (Level I) and the National Highway Institute (NHI 2001). Although and optional/additional (Level II) tests (shown in Table 2) for these publications do not specifically address EOT concrete, evaluating aggregates to be used in concrete pavements. The they discuss the selection of candidate projects, the sizing of concrete durability can be compromised through aggregate repairs, the installation of load transfer, material selection, reactivity (alkali-silica or alkali-carbonate reactivity) or aggre- construction procedures, and to some degree performance gate susceptibility to freeze-thaw damage. These topics are and cost considerations. Only limited discussions of material not covered in these guidelines, but relevant information is selection are contained in these documents, and little if any available elsewhere (Farney and Kosmatka 1997, ACI 2003a, guidance is provided for assessing the durability characteris- Folliard and Smith 2003, Schwartz 1987, and Stark 1976). tics of the EOT concrete mixtures. This chapter details the Another aggregate property that may impact EOT concrete state of the practice for mixture constituents and proportion- durability is the coefficient of thermal expansion (CTE) of the ing, construction practices, durability concerns, and test meth- aggregate, which strongly influences the CTE of the concrete. ods commonly used to assess durability. The CTE of a material is defined as the change in unit length per degree of temperature change. Differences in the CTE between aggregate and cement paste can lead to the develop- 2.1 MIXTURE CONSTITUENTS ment of thermal stresses within the concrete (Mindess et al. AND PROPORTIONS 2003) and in extreme cases may result in separation between The main difference between EOT concrete and normal the aggregate and the paste (Neville 1996). These differen- paving concrete is that strength gain occurs much more rapidly tial thermal movements--either between the aggregate and in EOT concrete, thus more cement, less water, admixtures, cement paste or between different aggregates in the same and aids to retain heat are commonly used. This section dis- concrete--could lead to deterioration (Lea 1971). In addi- cusses the various constituents and mixture proportioning of tion, because the CTE influences the thermal stresses devel- oped in concrete, its consideration is particularly important EOT concrete. in EOT concrete pavement materials selection. As previously stated, the CTE of concrete is strongly 2.1.1 Constituent Materials related to the proportion and type of coarse aggregate used. The CTE for the aggregate is generally lower than the coef- For the most part, EOT concrete is composed of the same ficient for cement paste. For example, the CTE is approxi- constituents as normal paving concrete. Coarse and fine aggre- mately 1113 × 10-6/°C (6.17.2 × 10-6/°F) for a quartzite
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6 TABLE 1 General distress criterion for full-depth repair of these materials (Kosmatka et al. 2002). These cements (FHWA 2003) have not been commonly used in EOT concrete projects in Pavement Type Distress Type Minimum Severity Level the United States because of their generally slower rate of Required for Full-Depth hydration. Repair Chemical Admixtures Jointed Plain and Blowup Low Jointed Reinforced Corner Break Low Concrete (JPC and D-Cracking Medium Chemical admixtures--such as air entrainers (AASHTO M JRC) Pavement Deterioration Adjacent to Medium 154), accelerators, and water reducers (AASHTO M 194)-- Existing Repair Joint Deterioration Medium (with faulting 6 are commonly added to EOT concrete mixtures during pro- mm [0.25 in.]) portioning or mixing to enhance the properties of freshly Spalling Medium mixed and/or hardened concrete. Descriptions of these and Reactive Aggregate Medium Transverse Cracking Medium (with faulting 6 other chemical admixtures can be found in a number of mm [0.25 in.]) sources (Kosmatka et al. 2002, Mehta and Monteiro 1993, Longitudinal Cracking High (with faulting 12 Mindess et al. 2003). It is reported that cement/admixture mm [0.5 in.]) Continuously Blowup Low interactions are not well understood and that compatibility Reinforced Punchout Medium (with faulting 6 problems can result in non-durable concrete (Kosmatka et al. Concrete mm [0.25 in.]) 2002, Mindess et al. 2003). Pavement (CRCP) Transverse Cracking Medium (with faulting 6 (Steel Rupture) mm [0.25 in.]) Localized Distress Medium Air Entrainers. Air-entraining admixtures are specified Construction Joint Medium Distress and tested under AASHTO M 154 and T 157, respectively. D-Cracking High Air-entraining admixtures are added just prior to or during Longitudinal Cracking High (with faulting 12 concrete mixing. When a high-range water reducer (HRWR) mm [0.5 in.]) Repair Deterioration High is used, the air entrainer should be added first to form a sta- ble air-void system that protects the hardened concrete against freeze-thaw damage and deicer scaling (Mindess et al. 2003). The entrained air also improves the workability of the fresh aggregate and 6 × 10-6/°C (3.3 × 10-6/°F) for a limestone aggre- concrete, thus helping reduce segregation and bleeding. gate, and in the range of 1820 × 10-6/°C (1011 × 10-6/°F) for The amount of entrained air required to protect normal con- cement paste (Mindess et al. 2003). crete depends on the exposure level and the nominal maximum Research has led to some correlation between CTE for con- aggregate size. The ACI recommended air contents for frost- crete and durability of mixtures. Lab tests have shown that resistant concrete (ACI 2003b) are reproduced in Table 3. concrete having higher CTEs are less resistant to temperature One concern for EOT concrete mixtures, especially those changes than concrete with lower CTEs (Neville 1996). made with an HRWR, is the ability to achieve a desirable air- void system in highcement-content mixtures (Whiting and Portland Cement Nagi 1998). Thus, not only should such mixtures be tested for total air, but the spacing factor should also be measured In many applications, the use of a standard AASHTO M during the mix design process (Mindess et al. 2003). 85 Type I cement can provide satisfactory results for EOT The air content of fresh concrete can be determined using concrete repairs. However, Type III cement is commonly AASHTO T 152 or T 196. Air content alone does not ensure used in EOT concrete materials because of its highearly- the adequacy of the air-void system, but relatively good cor- strength gain. The required chemical properties of Type III relations exist between air content and frost resistance for air- cements are similar to those of Type I, but Type III cements entrained concrete. In recent years, the Air Void Analyzer are ground more finely to promote the development of higher (AVA) has been used for air-void system characterization in early strength. In some cases, Type II cements have been fresh concrete, with some SHAs using it during concrete pave- used in EOT concrete materials. Regardless of the cement ment construction (FHWA 1996). The complete air-void sys- type used, the engineer must carefully evaluate the properties tem in hardened concrete can be assessed microscopically of the cement in the context of the long-term physical and using procedures described in ASTM C 457. It has been chemical stability and their effect on durability. observed in some mixtures, particularly those of high strength, Standard specifications for blended hydraulic cements are that adequate freeze-thaw durability exists even though the provided in AASHTO M 240. These cements are formed by air-void system parameters are judged to be inadequate. intimately blending portland cement with fine materials such as ground granulated blast-furnace slag, fly ash or other poz- Accelerating Admixtures. Accelerating admixtures meet- zolans, hydrated lime, and pre-blended cement combinations ing the requirements of Type C or E in AASHTO M 194 are
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7 TABLE 2 Recommended (Level I) and optional/additional (Level II) testing of aggregates for concrete pavements (Folliard and Smith 2003) Level Property Test Method I Absorption AASHTO T 84: Specific Gravity and Absorption of Fine Aggregate AASHTO T 85: Specific Gravity and Absorption of Coarse Aggregate Aggregate gradation AASHTO T 21: Sieve Analysis of Fine and Coarse Aggregate Properties of AASHTO T 11: Materials Finer than No. 200 Sieve and Mineral Aggregates by microfines Washing AASHTO T 176: Plastic Fines in Graded Aggregates and Soils by the Use of the Sand Equivalent Test Aggregate shape, AASHTO T 304: Uncompacted Void Content of Fine Aggregate angularity, and texture AASHTO TP 56: Uncompacted Void Content of Coarse Aggregate (As Influenced by Particle Shape, Surface Texture, and Grading) ASTM D 4791: Test Method for Flat and Elongated Particles in Coarse Aggregate Aggregate thermal AASHTO TP-60: Standard Test Method for the Coefficient of Thermal Expansion expansion of Hydraulic Cement Concrete Aggregate abrasion CSA A23.2-23A: Resistance of Fine Aggregate to Degradation by Abrasion in the Micro-Deval Apparatus AASHTO TP 58: Resistance of Coarse Aggregate to Degradation by Abrasion in the Micro-Deval Apparatus AASHTO T 96: Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angles Machine Elastic modulus ASTM C 469: Static Modulus of Elasticity and Poisson's Ratio of Concrete in Compression Polishing ASTM D 3042: Test for Acid Insoluble Residue in Carbonate Aggregates Aggregate strength British Standard 812 (Part 3): Aggregate Crushing Value Aggregate mineralogy ASTM C 295: Guide for Petrographic Examination of Aggregates for Concrete Alkali-aggregate ASTM C 295: Guide for Petrographic Examination of Aggregates for Concrete reactivity AASHTO T 303: Accelerated Detection of Potentially Deleterious Expansion of Mortar Bars Due to Alkali-Silica Reaction CSA A23.2-26A: Determination of Potential Alkali-Carbonate Reactivity of Quarried Carbonate Rocks by Chemical Composition Freezing and thawing CSA A23.2-24A: Unconfined Freezing and Thawing of Aggregates in NaCl resistance (D-cracking) Solution AASHTO T 104: Soundness of Aggregate by Use of Sodium Sulfate or Magnesium Sulfate (only magnesium sulfate is recommended) Iowa Pore Index Test Modified Washington Hydraulic Fracture Test (based on modifications detailed by Embacher and Snyder ) II Properties of AASHTO TP 57: Standard Test Method for Methylene Blue Value of Clay, microfines Mineral Fillers, and Fines Aggregate mineralogy X-ray diffraction (XRD) analysis Thermogravimetric analysis (TGA) X-ray fluorescence (XRF) analysis Alkali-aggregate ASTM C 1293: Test Method for Concrete Aggregates by Determination of Length reactivity Change of Concrete Due to Alkali-Silica Reaction Freezing and thawing AASHTO T 161 (modified Procedure C): Resistance of Concrete to Rapid resistance (D-cracking) Freezing and Thawing commonly used in EOT concrete repair materials. The Amer- acteristics are believed to be at least partly responsible for the ican Concrete Institute, in "Chemical Admixtures for Con- reduced freeze-thaw resistance exhibited in some mixtures crete," defines an accelerating admixture as "a material added containing calcium chloride accelerators (Neville 1996). to concrete for the purpose of reducing the time of setting and Calcium chloride is commercially available in an anhydrous accelerating early strength development" (ACI 2003c). and a dihydrate form. Commercial anhydrous calcium chlo- One group of accelerating admixtures contains a variety of ride is typically 94 to 97 percent calcium chloride by weight, soluble inorganic salts, such as calcium chloride, which is the whereas commercial flake products, which are close to dehy- best known and most commonly used accelerating admixture drate, typically are composed of 77 to 80 percent calcium chlo- because it is relatively inexpensive and readily available. ride by weight (ACI 2003c). Although opinions vary slightly, However, calcium chloride promotes corrosion of embedded the optimum dosage recommended is typically 2 percent for steel and may have other negative effects on concrete dura- Type I calcium chloride (88 percent pure), and 1.5 percent for bility, including increasing the amount of drying shrinkage anhydrous calcium chloride (ACI 2003c, Mindess et al. 2003). (Lackey 1992) and adversely affecting the pore structure Several commercial non-chloride accelerators conforming (Suryavanshi et al. 1995, Wang and Gillott 1990). These char- to AASHTO M 194 Type C requirements for accelerating
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8 TABLE 3 Recommended air contents for freeze-thaw distress resistant concrete (ACI 2003b) Nominal Maximum Average Air Content, Percent1 Aggregate Size, mm (in.) Moderate Exposure2 Severe Exposure3 9.5 (3/8) 6 7.5 12.5 (1/2) 5.5 7 19 (3/4) 5 6 25 (1) 5 6 37.5 (11/2) 4.54 5.54 75 (3) 3.54 4.54 150 (6) 3 4 1A reasonable tolerance for air content in field construction is ± 1.5 percent. 2 Exposure is outdoor in a cold climate where the concrete will be only occasionally exposed to moisture prior to freezing and where no deicing salts will be used. Examples are certain exterior walls, beams, girders, and slabs not in direct contact with soil. 3 Exposure is outdoor in a cold climate where the concrete may be in almost continuous contact with moisture prior to freezing or where deicing salts are used. Examples are pavements, bridge decks, sidewalks, and water tanks. 4 These air contents apply to the whole as for the preceding aggregate sizes. When testing these concretes, however, aggregate larger than 37.5 mm (11/2 in.) is removed by handpicking or sieving and the air content is determined on the minus 37.5 mm (11/2 in.) fraction of the mixture. (The field tolerance applies to this value.) From this, the air content of the whole mixture is computed. admixtures contain calcium nitrate and ammonium calcium cement content, and presence of other admixtures (Kosmatka nitrate as active ingredients. Others conforming to AASHTO et al. 2002). For Type A and Type E water reducers, the effect M 194 Type E requirements for water-reducing and acceler- on the air-void structure is unclear, with some sources report- ating admixtures and also conforming to Type C require- ing either no effect or an improvement (Kosmatka et al. ments contain calcium nitrate as a principal active ingredi- 2002) while others reporting possible adverse effects (Pigeon ent. Research has shown that calcium nitrite is useful as a and Plateau 1995). HRWRs, also called superplasticizers, are corrosion inhibitor in addition to its accelerating capabilities specified under AASHTO M 194 Type F and Type G and can (Neville 1996). Other non-chloride, non-corrosive accelera- reduce water content by 12 to 30 percent. In some instances, tors are available that contain compounds such as triethanol- they have application in EOT concrete mixtures where high amine, sodium thiocyanate, and calcium formate. cement contents and low w/c ratios are desired. This is par- It has been generally observed that concrete microstruc- ticularly true if the cement is finely ground, as are many Type ture produced in rapidly setting concrete is coarser and com- III cements. One drawback is that air voids produced in con- posed of more soluble hydration products, which in turn is crete made with HRWRs are often large, which increases the more prone to physical and chemical attack. It is therefore spacing factor and, on occasion, creates instability in the air- recommended that accelerators be used only when necessary void system (Kosmatka et al. 2002, Pigeon and Plateau 1995). and that the designer/engineer recognize that the use of accel- Thus, the fresh and hardened concrete properties of mixtures erators may have a negative impact on the long-term dura- containing water reducers should be thoroughly evaluated bility of the concrete. during design to determine the extent of detrimental inter- actions that may occur. Water-Reducing Admixtures. Water-reducing admixtures are added to reduce the quantity of mixing water required 2.1.2 State-of-the-Practice to produce concrete of a given consistency. This reduction Mixture Proportioning allows for a reduction in the water-to-cement (w/c) ratio while maintaining a desired slump, thus increasing strength This section presents a brief summary of common practice while reducing permeability. A reduction in water content by regarding EOT concrete mixture proportioning as presented 5 to 10 percent is obtainable through the use of conventional in publications by the FHWA (2003), ACPA (1995), and the water reducers that are specified under AASHTO M 194 NHI (2001). In these publications, it is noted that EOT con- Type A. This class of water reducer will typically retard set, crete repair materials use similar constituents and propor- so accelerators are often added to offset this effect. Water tioning as normal paving concrete, except that higher cement reducers that act as accelerators are specified under AASHTO contents and lower w/c ratios are common. In addition, mate- M 194 Type E. rials that lead to accelerated strength gain--such as Type III The effect of water reducers on the fresh concrete proper- cement, chemical accelerators, and water-reducing admix- ties varies with the chemical composition of the admixture, tures--are also used. Specifically, the following items are the concrete temperature, cement composition and fineness, reported in these publications:
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9 · Type I or III cements are commonly used in EOT con- for opening to traffic is 1.7 MPa (250 psi) for third-point crete. Additional water may be required to enhance work- loading and 2.1 MPa (300 psi) for center-point loading, and ability with Type III cements. The use of a water reducer the compressive strength criterion is 13.8 MPa (2,000 psi) can reduce this need for additional water (ACPA 1995). (FHWA 2003). The NHI document also states that having a · Common cement contents for mixtures that are to be strength requirement is preferable and that maturity meters opened to traffic within 24 hours range from 385 to or pulse-velocity devices may be useful for monitoring the 530 kg/m3 (650 to 890 lb/yd3), with more cement being strength development of very highearly-strength materials added for earlier opening times. For 24-hour acceler- (e.g., 4 hours or less of curing time). ated strength concrete, a draft specification stipulates All of the 16 states except California that specify use of a minimum cement content of 446 kg/m3 (750 lb/yd3) calcium sulfoaluminate (CSA) cement used either Type I or (FHWA 2003). Type III portland cement in the 6- to 8-hour EOT concrete · The w/c ratio in EOT concrete is typically between 0.40 materials. When specified, the minimum cement contents and 0.48. A draft specification for 24-hour accelerated varied, ranging from 440 to 534 kg/m3 (740 to 900 lb/yd3) for strength concrete stipulates a maximum w/c ratio of 0.45 Type I and 390 to 490 kg/m3 (660 to 825 lb/yd3) for Type III. (FHWA 2003). The use of accelerators was specified for mixtures contain- · An accelerator is commonly employed and is almost ing Type I cement, with the most common accelerator being a necessity for mixtures that are to be opened in 6 to calcium chloride. Notable exceptions to this standard were 8 hours. The most common accelerator is calcium chlo- New Jersey and Pennsylvania, which prohibited the use of a ride, which is commonly added at 1 percent by weight of chloride-based accelerator. Some of the mixtures proportioned cement when the air temperature exceeds 27°C (80°F) with Type III cement did not specify the use of an accelera- and up to 2 percent by weight of cement when the air tor, relying on the early strength gain of the cement. The w/c temperature is lower. ratios for the 6- to 8-hour EOT concrete mixtures vary widely, with maximum values ranging from 0.33 to 0.49. In general, Tables 4 and 5 summarize SHA specifications for EOT higher w/c ratios were allowed for mixtures containing Type concrete repair materials for 6- to 8-hour opening time and III cement. In no instance was a supplementary cementitious 20- to 24-hour opening time, respectively. material (e.g., fly ash, ground granulated blast furnace slag [GGBFS], and silica fume) specified for use in 6- to 8-hour EOT concrete mixtures. Six- to 8-hour EOT Concrete Admixtures commonly specified for use in 6- to 8-hour EOT concrete mixtures included air entrainers, accelerators, Table 4 summarizes the mixture characteristics of the 6- to and water reducers. In no case was the type of air-entraining 8-hour EOT concrete specified by 16 SHAs. Although time agent specified, but instead air content was specified either to opening was frequently stipulated in the specifications, directly or through reference to the SHA's standards for nor- strength requirements were also used. For example, the time- mal paving concrete. The most commonly specified acceler- to-opening criterion presented in Table 4 vary from as early ator was calcium chloride, either in solution or in flakes. as 4 hours (Kansas and Ohio) to as late as 12 hours (Mary- Addition rates ranged from 1 to 2 percent, and in many cases land and Minnesota). In some cases, only a time to opening the recommended rate was based on ambient conditions, or a strength criterion was established, and some SHAs used with cooler temperatures requiring an increase in the calcium a strength criterion in addition to time to opening. Florida, for chloride added. Other accelerators allowed included non example, specified that the compressive strength must exceed chloride-based admixtures meeting AASHTO M 194 Type C 21 MPa (3,000 psi) in 24 hours while allowing a 6-hour time or Type E. The Type E admixture also acts as a water reducer, to opening. In New York, the repair was opened to traffic having the added benefit of being able to reduce the w/c ratio once the surface temperature of the repair reached 65°C while maintaining the same workability. Water reducers were (150°F). Although it is difficult to glean from these specifi- not often specified in SHA specifications for 6- to 8-hour cations and special provisions the exact strength require- EOT concrete materials. When specified, water reducers ments during the initial 6- to 8-hour period, the required com- conforming to AASHTO M 194 Type A, Type D, Type E, or pressive strength at opening varied from 8.3 to 24.0 MPa Type F were permitted. In Ohio, which is the one state spec- (1,200 to 3,500 psi), whereas the required minimum flexural ifying a Type D admixture, the retardation effect of the admix- strength (as measured by third-point loading) ranged from ture would likely be offset by the specified high cement 1.8 to 2.8 MPa (260 to 400 psi). content (534 kg/m3 [900 lb/yd3]) and relatively low w/c ratio In NHI's PCC Pavement Evaluation and Rehabilitation, (<0.40) of the mixtures. As noted previously, there are con- both minimum strength requirements and time to opening cerns that the use of Type F admixtures (high-range water requirements are recognized as being acceptable (NHI 2001). reducers) may result in instability of the entrained air-void According to this publication, the flexural strength criterion system.
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TABLE 4 Summary of SHA specifications for 6- to 8-hour EOT repair materials in 2000 Mixture Opening Cement Cement w/c Coarse Fine Mineral Water State Designation Criterion Type Factor Ratio Aggregate Aggregate Accelerator Air Content Admixture Reducer AR Accelerated >14 MPa (2,000 psi) Type III NS NS No. 57 NS CC or other NS NS NS Strength completed @ 6 hours CA Type >2.8 MPa (400 psi) CSA NS NS 37.5 or 25 NS Retarder and NS NS NS FSHCC flexural @ 8 hours mm (1.5 or Type C used 1.0 in.) maximum FL Patching >21 MPa (3,000 psi) NS >446 kg/m3 < 0.45 57 Stone NS 1% CC or 2 to 6% NS Type F completed @ 24 (750 lb/yd3) Type C allowed hours 6-hour opening IL Class PP(2) 8-hour opening Type I 440 kg/m3 < 0.38 1,020 kg/m3 665 kg/m3 Type E or 4 to 6% NS Type F (740 lb/yd3) (1,720 (1,120 Type C lb/yd3) lb/yd3) IA Class M 5-hour opening Type I or ~470 kg/m3 ~0.33 Volume Volume CC 5% w/ CC No NS Type II (790 lb/yd3) specified specified 6.5% w/o Class FF 5-hour opening Type III ~490 kg/m3 ~0.43 Not Allowed 6.0% Yes (825 lb/yd3) KS Accelerated 4- to 6-hour opening Type III >390 kg/m3 NS NS NS 1 to 2% CC NS NS NS Cure (658 lb/yd3) MD 6 hours or 7 > 17 MPa (2,500 psi) Type I >445 kg/m3 < 0.42 No. 57 NS CC or NC 5.5% NS Type F, hours completed @ 12 (750 lb/yd3) Type C Melamine hours MN 3A32HE 12-hour opening time Type I 30% extra NS NS NS Type E 6.5% NS Type E MI Type SLP > 2.0 MPa (290 psi) Type I 502 kg/m3 NS MDO T 6A NS CC 5.5% NS NS flexural @ 8 hours (846 lb/yd3) MO 4 hours > 24 MPa (3,500 psi) Type I or 475 kg/m3 (800 NS NS NS CC or other NS NS NS completed III lb/yd3) for Type I NJ VHES > 2.4 MPa (350 psi) Type I w/ >390 kg/m3 0.37 No. 57 NS NC required 6.5% NS Type F flexural @ 6.5 hours accelerator (658 lb/yd3) or Type III NY Patch Surface temperature Type III 490 kg/m3 0.39 NYDOT NS 2% CC 6.0% NS NS of 65oC (150oF) (825 lb/yd3) CA2 OH Class FS 2.8 MPa (400 psi) Type I 534 kg/m3 < 0.40 No. 57, No. NS 1.5% CC or 6.0% NS Type D flexural @ 4 hours (900 lb/yd3) 6, No. 67, or other No. 8 PA Accelerated 8.3 MPa (1,200 psi) NS NS NS No. 57 Type A NC allowed 6.0% NS NS completed @ opening 10 MPa (1,450 psi) completed @ 7 hours TX Class K 2.9 MPa (420 psi) Type III 390 kg/m3 < 0.49 Grade 2 or 3 Grade 1 Type C NS NS Type A flexural @ 24 hours, (658 lb/yd3) FM 2.6 to Open @ 1.8 MPa 2.8 (260 psi) flexural WI Special 21 MPa (3,000 psi) NS >502 kg/m3 NS NS NS CC or other NS NS NS HES completed @ 8 hours CC: calcium chloride. CSA: Calcium sulfoaluminate cement. NC: non-chloride. NS: not specified. VHES: very high early strength.
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TABLE 5 Summary of SHA specifications for 20- to 24-hour EOT repair materials in 2000 Opening Cement Cement w/c Coarse Fine Mineral Water State Mixture Criterion Type Factor Ratio Aggregate Aggregate Accelerator Air Content Admixture Reducer Designation AR HES >21 MPa (3,000 psi) Type I 25% extra NS NS NS NS NS NS NS completed @ 24 Type III NS hours GA 24-Hour >17 MPa (2,500 psi) Type I or 420 kg/m3 < 0.45 NS NS CC 3 to 6% NS NS Accelerated completed @ 24 Type III (700 lb/yd3) Or Type E hours IL Class PP(1) > 22 MPa (3,100 psi) Type III or NS NS NS NS Accelerator NS NS NS completed > 4.2 MPa Type I required (600 psi) flexural @ 48 hours IN High Early 3.8 MPa (550 psi) Type I or >335 kg/m3 <0.42 NS NS NS 6.5% 10% flyash Type A flexural @ 48 hours Type III (564 lb/yd3) <0.45 15% GGBFS KS Normal 24-hour opening Type I or II >445 kg/m3 NS NS NS No NS NS NS Cure (750 lb/yd3) MD 24 hours > 17 MPa (2,500 psi) Type I >475 kg/m3 NS NS NS NS NS NS Type F completed @ 12 (800 lb/yd3) hours MN 3A32HE 24-hour opening time Type I 30% increase NS NS NS NS 6.5% NS Type A MI Type P-MS > 3.5 MPa (500 psi) Type I 502 kg/m3 NS NS NS CC below 5.5% NS NS flexural @ 24 hours (846 lb/yd3) 18oC (65oF) MO 24 hours >24 MPa (3,500 psi) Type I 475 kg/m3 (800 NS NS NS NS NS NS NS completed lb/yd3) for Type I OH Class MS 2.8 MPa (400 psi) Type I 475 kg/m3 < 0.43 No. 57, No. NS NS 6.0% NS Type D flexural @ 24 hours (800 lb/yd3) 6, No. 67, or No. 8 TX Class K 2.1 MPa (300 psi) Type I or 390 kg/m3 < 0.53 Grade 2 or 3 Grade 1 Type C NS NS Type A or "Modified" flexural @ 24 hours Type III (658 lb/yd3) FM 2.3 to allowed D 335 kg/m3 3.1 (564 lb/yd3) CC: calcium chloride. GGBFS: ground granulated blast furnace slag. HES: high early strength. NC: non-chloride. NS: not specified.