Manual for Emulsion-Based Chip Seals for Pavement Preservation (2011) / Chapter Skim
Currently Skimming:
Appendix - Recommended Test Methods
Appendix - Recommended Test Methods
Pages 29-65
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 29... ...
A P P E N D I X Recommended Test Methods CONTENTS Recommended Standard Method of Test for Embedment Depth of Chip-Seal Aggregates in the Lab and the Field, 30 Recommended Standard Method of Test for Laboratory Chip Loss from Emulsified Asphalt Chip Seal Samples, 39 Recommended Standard Method of Test for Measuring Moisture Loss from Chip Seals, 53 Recommended Standard Method of Test for Recovery of Asphalt from Emulsion by Stirred-Can Method, 59 Recommended Standard Method of Test for Determining the Strain Sensitivity of Asphalt Emulsion Residue Using Strain Sweeps Performed on a Dynamic Shear Rheometer (DSR)
|
From page 30... ...
SUMMARY OF TEST METHOD 3.1 Where the void ratio of an area of chip seal may be estimated with acceptable accuracy, and where voids (Note 1) between all chip-seal particles are filled with a given mass of glass beads of known packing density, the average height of beads within the chip seal layer may be determined.
|
From page 31... ...
Chip Seal Bedding Plane Height of average particle Asphalt Aggregate Imaginary undulating surface: upper bound of chip seal voids H E Volume of chip seal voids T Voids filled by asphalt Profile of voids remains unchanged at all embedments Chip Seal Bedding Plane Height of average particle Asphalt Aggregate Imaginary undulating surface: upper bound of chip seal voids H E T Volume of chip seal voids Note 1 -- For the purposes of this test method, it is assumed that the actual chipseal voids are those that exist above the asphalt surface and below the profile of an imaginary, three-dimensionally undulating, flexible membrane that is draped over aggregate particles and forced to come into contact with the peak of each particle (see Figure 1 and Figure 2)
|
From page 32... ...
Equivalent chip seal. Chip Seal Bedding Plane Height of average particle Volume of chip seal voids H E T Asphalt Aggregate In the second procedure, the "submerging procedure," a known, variable volume of glass beads is used to completely cover all chip-seal particles within a fixed area to a fixed level above the height level of the chip seal's average particle (Figure 4)
|
From page 33... ...
, of area "R," under laboratory chip seal Top of mold Imaginary undulating surface: upper bound of chip seal voids H E T "C" is the volume of all beads deposited directly on the chip seal of fixed area "A" Mold of area "W" Glass beads, "B," in voids Note 3 -- The submerging procedure, which may be used for any degree of embedment, has been devised primarily to account for the situation, at very high embedment depths, where the asphalt surface intersects the imaginary membrane defined in Note 1. In this situation, where some particle peaks are covered, it may become difficult to spread the beads to follow the required profile illustrated in Figure 2.
|
From page 34... ...
Performance in terms of high skid resistance and reduced construction cost, on the other hand, is likely to decrease with increased embedment beyond a certain level. 4.3 Additionally, embedment depth evaluation is important simply because it is often the only practical means by which an apparently sound field chip seal may be evaluated.
|
From page 35... ...
5.7 Field Mold – When carrying out the submerging procedure in the field, a field mold is to be used to form the glass beads over a fixed area of chip seal. The field mold is to be built up using a perimeter gasket wall and a flat metal surface with a cutout.
|
From page 36... ...
of glass beads, which will be more than enough to cover the chip seal and fill the mold. 8.2 For the lab procedure, place the specimen chip seal into the mold or form the mold around the specimen, ensuring that the mold and the specimen are flat and level and that complete submergence of the chip seal will be achieved.
|
From page 37... ...
on the chip-seal surface, filling only voids between particles ; C = total volume of beads (mm 3 ) deposited directly on the chip-seal surface area; S = thickness of base, or sheet, on which specimen chip seal has been constructed (mm)
|
From page 38... ...
of base, or sheet, on which specimen chip seal has been constructed; R = area of base (mm2) ; and A = plan area of chip seal covered by beads (mm2)
|
From page 39... ...
and Voids in Aggregate 2.2 ASTM Standards: • Coarse Aggregate • T 27, Sieve Analysis of Fine and Coarse Aggregates • T 2, Practice for Sampling Aggregates • T 40, Practice for Sampling Bituminous Materials • M 140, Specification for Emulsified Asphalt • M 208, Specification for Cationic Emulsified Asphalt • D 226, Specification for Asphalt-Saturated Organic Felt Used in Roofing and Waterproofing T 85, Test Method for Density, Relative Density (Specific Gravity) , and Absorption of • D 7000, Standard Test Method for Sweep Test of Bituminous Emulsion Surface Treatment Samples
|
From page 40... ...
Asphalt emulsion and a single layer of aggregate chips are applied to an asphalt felt disk. The sample is then conditioned in an oven to arrive at a prescribed emulsion/chip moisture content before testing.
|
From page 41... ...
shall be attachable to the mixer and capable of a free-floating vertical movement of 19 ± 1 mm and having the dimensions listed in the table below. The total mass of the brush head and the attached weight shall be 1,500 ± 15 g.
|
From page 42... ...
See Appendix A2 for guidelines to calculate the required emulsion volume (and, therefore, the required template gauge) for varying emulsion residual contents and aggregate sizes.
|
From page 43... ...
The plates are used to position and suspend aggregate chips. When pulled away, the sliding plates no longer suspend the aggregate chips and these fall onto the asphalt emulsion.
|
From page 44... ...
slid from beneath aggregate chips, the chips fall vertically onto the asphalt emulsion and assume the same orientations that were given to them on the plates prior to sliding. See Figure 6.
|
From page 45... ...
Note 4 -- Emulsion volume will vary according to the void volume that exists between aggregate particles and the residual content of the emulsion. Asphalt emulsion coverage rates are to be calculated for each source and for each combination with different aggregates.
|
From page 46... ...
8.2 Immediately position the sliding-plate chip-dropper on the working platform, over the asphalt disk, and apply the pre-weighed aggregate sample onto the asphalt emulsion. Once the aggregate has been placed on the sample, compact the aggregates using the sweep test compactor three half cycles in one direction and three half cycles in a perpendicular direction to set the aggregate.
|
From page 47... ...
, and relative humidity based on desired field performance. Note 6 -- Typically, where the performance of the binder–aggregate combination is being tested at various emulsion cure levels, specimens are cured at any convenient temperature and for any time period that provides the required specimen cure level.
|
From page 48... ...
The preceding manufacture and testing procedures account for and test the relative strength of the bond developed between asphalt binder and aggregate particles within the chip seal itself. The required aggregate mass and asphalt cement volume depend on the average aggregate particle dimensions, on an assumed eventual de gree of compaction of the aggregate particles, and on the assumption that each particle will eventually lay on its widest face.
|
From page 49... ...
The following useful guidelines for the calculation of required aggregate and em ulsion masses used in the manufacture of laboratory specimens are taken from the McLeod and the modified Kearby single-surface-treatment design methods respectively referenced in the FHWA Asphalt Emulsion Manual , FHWA-IP-79-1, and the USDOT Field Manual on Design and Construction of Seal Coats , Research Report 214-25, July 1981.
|
From page 50... ...
of the loose aggregate, and the ultimate average mat depth (H ) , in conjunction with an assumed ultimate void volume (0.4V )
|
From page 51... ...
It may be helpful to assume that the applied specimen aggregate has a void volume of 80% of that in the loose weight condition. A2.6 The preceding standard is intended to allow performance evaluation of a combination of asphalt emulsion and aggregate chips as well as relative performance of several combinations of asphalt emulsions with aggregate chips at a certain level of cure.
|
From page 52... ...
It provides the relative performance of chip-seal treatment materials, specifically those of a single surface treatment exhibiting compactly placed and oriented aggregate particles one stone in depth. Through the use of this standard, and as a result of the ability to precisely place a predetermined aggregate mass, it becomes possible to calculate the precise volume of required asphalt emulsion.
|
From page 53... ...
SUMMARY OF TEST METHOD 3.1 By quantifying the mass loss of a specimen chip seal, which is significantly equivalent to a field chip seal, and where the emulsion spray rate, the emulsion residual content, and initial aggregate moisture content can be approximated, it becomes possible to estimate the specimen's cure level at different monitoring points throughout a workday. 3.2 In this test, a chip-seal specimen is manufactured by site equipment on a board placed on the roadway while the field chip seal is being built.
|
From page 54... ...
5.4 Infrared Thermometer – This is used to check temperatures of the field chip seal and the specimen chip seal. 5.5 Drying Pan – This metal pan is used to dry sampled aggregate where the moisture content appears to be high or in question.
|
From page 55... ...
Configured specimen board. 6.2 Aggregate and Asphalt Emulsion – The chip-seal specimens are laid down by the distributor and chipper in the course of placing the actual field chip seal.
|
From page 56... ...
Estimate the moisture content of the asphalt emulsion to be the mass loss expressed as a percentage of the initial asphalt emulsion mass. The asphalt emulsion's residual content (R)
|
From page 57... ...
(4) 8.5 The percent moisture content of asphalt emulsion at cure level (L)
|
From page 58... ...
, G = specific gravity of the asphalt emulsion, D = mass of dry specimen aggregate (g) , S = initial specimen mass (including board)
|
From page 59... ...
2. SUMMARY OF METHOD 2.1 The water in the asphalt emulsion is evaporated under a nitrogen atmosphere at an elevated temperature.
|
From page 60... ...
6.2 Weigh 1,250 ± 0.5 g of asphalt emulsion and add to the gallon can, then wrap the heating tape around the can until the tape covers the bottom half. Cover the side of the can with the heat insulation pad and place the container underneath the laboratory mixer.
|
From page 61... ...
. The water evaporation rate is low in this region, and power input primarily increases the temperature.
|
From page 62... ...
62 50 100 150 200 250 300 350 0 50 100 150 Temperature (F)
|
From page 63... ...
. This test method is method, the asphalt binder is the residue obtained by removing the water from a water- based asphalt emulsion.
|
From page 64... ...
7. SAMPLE 7.1 The sample is the residue after the water is removed from the water-based asphalt emulsion.
|
From page 65... ...
Note whether the sample is wholly or partially adhered to the plates, and note whether the sample has a ductile or a brittle break when the plates are pulled apart. 8.8 Generate a plot of dynamic shear modulus versus time.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.