Details:

Creators:
Buss, Ashley ; Rashwan, Mohamed ; Williams, R. Christopher
Buss, Ashley ; Rashwan, Mohamed ; Williams, R. Christopher Less -
Corporate Creators:
Iowa State University. Institute for Transportation
Corporate Contributors:
Iowa. Highway Research Board ; Iowa. Dept. of Transportation
Iowa. Highway Research Board ; Iowa. Dept. of Transportation Less -
Subject/TRT Terms:
[+]
Aggregates Asphalt Asphalt Concrete Pavements Testing Warm Mix Paving Mixtures
Publication/ Report Number:
TR-599
Resource Type:
Tech Report
Geographical Coverage:
Iowa
Edition:
Final report.
Corporate Publisher:
Iowa State University. Institute for Transportation
Abstract:
The implementation of warm-mix asphalt (WMA) is becoming more widespread with a growing number of contractors utilizing various WMA technologies. Early research suggests WMA may be more susceptible to moisture damage than traditional hot-mix asphalt (HMA) mixes. The objectives of this study are to test the binder and mix properties of WMA technologies for both field- and laboratory-produced mixes to determine the performance of WMA compared to traditional HMA. Field- and laboratory-produced mixes were studied. The laboratory-produced mixes compared HMA control mixes with WMA mixes that had the same mix design. The WMA technologies used for the laboratory study were Advera, Sasobit, and Evotherm. The field study tested four WMA field-produced mixes. Each of the four mixes had a corresponding control HMA mix. The WMA technologies used in the field study included: Evotherm 3G/Revix, Sasobit, and Double Barrel Green Foaming. The three main factors for this study were WMA/HMA, moisture-conditioned/not moisture-conditioned, and reheated/not reheated. Mixes were evaluated based on performance tests. Binder testing was performed to determine the rheological differences between HMA and WMA binders to determine if binder grade requirements change with the addition of WMA additives. The conclusions of this study are as follows: Reduced mixing and compaction temperatures were achieved; Statistical differences were found when comparing tensile strength ratio (TSR) values for both laboratory- and field-produced mixes. In the laboratory, none of the WMA additives performed as well as the HMA. For the field mixes, all TSR values passed Iowa’s minimum specification of 0.8 but, on average, WMA is lower compared to HMA TSR values; Dynamic modulus results show that, on average, HMA will have higher dynamic modulus values. This means the HMA exhibits stiffer material properties compared to WMA; this may not necessarily mean superior performance in all cases; Flow number results show that WMA has reduced flow number values compared to HMA. The only exception was the fourth field mix and weather delayed production of the control mix by nine days. The laboratory mixes showed that flow number values increased significantly with the addition of recycled asphalt pavement (RAP); and, In the laboratory study, Advera reduced TSR values. Given that Advera is a foaming agent, the increase in moisture susceptibility is likely attributed to the release of water necessary for the improvement of the workability of the asphalt mixture.
Format:
PDF
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:39387313ebe5584508f2f92bb19ecebbf6449566dc97ff84f4a61e6888ceb1d1
Download URL:
https://rosap.ntl.bts.gov/view/dot/20645/dot_20645_DS1.pdf
File Type:

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