Investigation of the CoreLok for Maximum, Aggregate, and Bulk Specific Gravity Tests

Sholar, Gregory A.; Page, Gale C.; Musselman, James A.; Upshaw, Patrick; Moseley, Howard

doi:10.3141/1907-16

Cited by 5 publications

(1 citation statement)

References 2 publications

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“…Maximum Specific Gravity of raP and Cir Sholar et al evaluated a low-absorption (1% to 2%) limestone RAP with D6857 and T 209. The difference between the D6857 and T 209 and between the D6857 and T 209 SSD G mm values was 0.002 (4). The closeness between these methods (difference of 0.002) was attributed to the low-absorption aggregate.…”

Section: Maximum Specific Gravity Of Asphaltmentioning

confidence: 82%

Vacuum Sealing–Based Volumetric Density Measurement Approach for Cold In-Place Recycling

Cox

Howard

2014

Transportation Research Record: Journal of the Transportation R

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Recent economic limitations have fostered increased use of pavement rehabilitation methods such as cold in-place recycling (CIR). CIR could be more appealing to departments of transportation provided variability were lower and performance were more predictable. Because of the nature of the materials and construction processes, CIR is likely to be more variable than plant-mixed asphalt, and it is believed that the performance variability of CIR can be reduced through enhanced density control. The many density control methods described in the literature for CIR are often vague. This study used ASTM D6857 vacuum sealing to obtain the maximum theoretical specific gravity ( Gmm) of reclaimed asphalt pavement (RAP) and a gravity-proportioning equation to estimate CIR Gmm (specific gravity after cement, emulsion, or a combination is mixed with RAP). Vacuum sealing was also used to obtain the bulk specific gravity ( Gmb) of compacted CIR (AASHTO T 331). In all, 240 Gmm and 156 Gmb tests were conducted. D6857 and AASHTO T 209 detect differences between RAP and hot-mix asphalt Gmm, but the differences led to manageable errors for CIR density control that should still allow for some improvements over many current practices. The equation developed in the study estimated CIR Gmm with reasonable error, and T 331 suitably characterized CIR Gmb at the often high air void levels that were observed. The findings show that CIR Gmm and Gmb, as determined by vacuum sealing and the gravity-proportioning equation, constitute a reliable, convenient, and implementable approach to controlling density and likely reducing performance variability.

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Section: Maximum Specific Gravity Of Asphaltmentioning

confidence: 82%

Vacuum Sealing–Based Volumetric Density Measurement Approach for Cold In-Place Recycling

Cox

Howard

2014

Transportation Research Record: Journal of the Transportation R

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Effect of Cement Kiln Dust and Rock Dust as Mineral Fillers on Bulk Specific Gravity of Fine Aggregates

Mitchell

Link

Gupta

et al. 2011

Journal of Testing and Evaluation

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The bulk specific gravity (Gsb) of aggregates is a critical parameter in the design of asphalt mixes. In the Superpave volumetric mix design, Gsb is used to determine the amount of asphalt binder absorbed by aggregates and the percentage of voids in the mineral aggregate. Problems with the current test methods of measuring the Gsb of fine aggregates, i.e., AASHTO T84 or ASTM C128, have been reported in some previous studies as well as in the current study. These standard test methods remain questionable under certain conditions: (1) When rough and angular as well as small and varying particle size distributions of fine aggregates are present and (2) when water reactive mineral fillers (passing No. 200 sieve) are added to fine aggregates. This study examined the addition of two selected mineral fillers, namely, Cement Kiln Dust (CKD) and rock dust, on the overall Gsb of fine aggregates by employing the AASHTO T84 and the CoreLok-Aggplus test procedures. When using the AASHTO T84 test method, the overall Gsb values reduce for both the additives. When using a newly developed CoreLok method, the Gsb values increased for rock dust up to 10 %, beyond which a reduction is observed. With CKD, the Gsb values show an increase for up to 6 % addition of it and then a decrease is observed. The data suggest that the AASHTO T84 test method may not be applicable in the presence of CKD due to the chemical reactions in the presence of water and the formation of cementitious products. A possibility of chemical reaction due to the presence of limestone in the rock dust and its fine gradation influence the results of the AASHTO T84 test method. Thus, use of the CoreLok method appears more appropriate in the presence of such reactive materials. To further analyze the problem, the specific surface area of fine aggregates and mineral fillers was measured using water vapor and nitrogen adsorption methods. This study also reveals that angular fine aggregates with a high angularity and rough surface texture pose significant difficulty in measuring Gsb by the AASHTO T84 test method.

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Investigating the Consistency of Asphalt Density Measurement Methods Over a Wide Range of Air Voids

Howard

Doyle

2014

Journal of Testing and Evaluation

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The overall purpose of this paper is to identify the most reliable bulk mixture specific gravity (Gmb) measurement method for dense graded asphalt concrete that can be used for a wide range of air voids and specimen types. A secondary purpose is to identify ranges of conditions where less established Gmb measurement methods are suitable. A comprehensive literature review was performed to identify promising density test methods for further study. Findings from studies comparing AASHTO T166 (saturated surface dry method) and AASHTO T331 (Corelok method) were used to provide a succinct summary of the relative behaviors of the two methods at mix design, performance testing, and field construction air void levels. Density measurement was performed using four methods (AASHTO T166, T269, T331, and TP82) on dense graded mixture specimens. In total, approximately 2500 data points were used herein, with approximately 30 % of this total coming from literature review and 70 % coming from the authors of this paper. Review of literature along with the evidence presented in this paper indicates that T331 is the most reasonably accurate and versatile Gmb measurement method for a wide range of air voids all the way from mix design through performance testing to construction acceptance testing. T331 has also been recommended (or at least evaluated favorably) by several previous researchers over the last ten years. Based on the evidence presented in this paper, the provisional TP82 test method in its current form does not provide acceptable Gmb measurements relative to T166 or T331 over a wide range of air voids. The magnitude of the discrepancy begins to increase dramatically as air voids increase.

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Investigation of the CoreLok for Maximum, Aggregate, and Bulk Specific Gravity Tests

Cited by 5 publications

References 2 publications

Vacuum Sealing–Based Volumetric Density Measurement Approach for Cold In-Place Recycling

Vacuum Sealing–Based Volumetric Density Measurement Approach for Cold In-Place Recycling

Effect of Cement Kiln Dust and Rock Dust as Mineral Fillers on Bulk Specific Gravity of Fine Aggregates

Investigating the Consistency of Asphalt Density Measurement Methods Over a Wide Range of Air Voids

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