US transportation agencies have been increasingly using recycled asphalt shingles (RAS) in hot mix asphalt (HMA) applications over the last 25 years. Initial use of RAS started with recycled post-manufacturers shingles, but now agencies are showing a growing interest in using post-consumer (tear-off) RAS in asphalt applications. Postconsumer asphalt shingles typically have 20 to 30 percent asph...

US transportation agencies have been increasingly using recycled asphalt shingles (RAS) in hot mix asphalt (HMA) applications over the last 25 years. Initial use of RAS started with recycled post-manufacturers shingles, but now agencies are showing a growing interest in using post-consumer (tear-off) RAS in asphalt applications. Post-consumer asphalt shingles typically have 20 to 30 percent asp...

In this study, nanoindentation was conducted to extract the load-displacement behaviour and the nanomechanical properties of asphalt concrete across the mastic, matrix, and aggregate phases. Further, the performance of hydrated lime as an additive was assessed across the three phases. The hydrated lime containing samples have greater resistance to deformation in the mastic and matrix phases, in...

Organisms of the genera Pseudomonas, Chromobacterium, and Bacillus capable of degrading asphalt were isolated by enrichment cultures. The asphalt degradation by these organisms varied from 3 to 25% after incubation for 1 week. The effects of temperature, pH, and atmosphere of incubation on asphalt degradation were investigated and were shown to vary with different organisms on the same substrate.

This work presents a theoretical/numerical study of the micromechanical behavior of asphalt concrete. Asphalt is a heterogeneous material composed of aggregates, binder cement and air voids. The load carrying behavior of such a material is strongly related to the local load transfer between aggregate particles, and this is taken as the microstructural response. Numerical simulation of this mate...

Asphalt pavement recycling has grown dramatically over the last few years as the preferred way to rehabilitate existing asphalt pavements. Rehabilitation of existing asphalt pavements has employed different techniques; one of them, cold in-place recycling with foamed asphalt (CIR-foam), has been effectively applied in Iowa. However, Iowa’s current cold in-place recycling (CIR) practice utilizes...

After years of use, there’s oil loss on the asphalt pavement. bond strength aggregate decreases. Loose threshing is serious. In order to improve pavement performance, Extend service life pavement, Improve safety aircraft operation. we test AC-20 modified mixture runway Da Lian Airport from many factors, including raw materials, admixtures, gradation design, optimum ratio stone, then find best w...

MATERIALS Pavement Core Samples COAL TAR AND ASPHALT CEMENT SAMPLES METHODS OF ANALYSIS Binder Content PAH Analysis Analysis of Phenols Modified Ames Assay RESULTS Coal Tar and Asphalt Cement Core Sample Analyses COMPARISON OF CORE SAMPLES WITH U.S. AND EUROPEAN ASPHALT AND COAL TARS COMPARISON OF DIN METHOD FOR PHENOLS WITH THE CORE SAMPLES COMPARISON OF MODIFIED AMES TEST RESULTS DISCUSSION C...

After years of use, there’s oil loss on the asphalt pavement. bond strength aggregate decreases. Loose threshing is serious. In order to improve pavement performance, Extend service life pavement, Improve safety aircraft operation. We test AC-20 modified mixture taxiway and runway Chang Sha Airport from many factors, including raw materials, admixtures, gradation design, optimum ratio stone, th...

Asphalt paving is a specific type of construction work: the machines and materials constantly move while the asphalt mixture constantly cools down. The machine operators do have a clear goal – to provide an equally distributed and uniformly compacted asphalt layer in time-restricted conditions. But what does it mean in particular? In reality, the asphalt should be compacted to a certain degree ...