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Abstract

The problem of recycled materials application in road construction is one of the key issues in contemporary road engineering. This article describes attempts to produce a hot mix asphalt (HMA) mixture entirely from processed reclaimed asphalt pavement (RAP) material. Due to the binder ageing process, rejuvenating agent was a necessary additive to the mixture. The mixture was tested to determine its parameters, including the content of voids, fatigue life, rutting resistance, stiffness and water sensitivity. The test results demonstrated that the rejuvenated RAP mixture is not inferior to fresh produced mixtures in terms of physical and strength parameters. Such results are, however, conditional on appropriate handling of the RAP material.

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Authors and Affiliations

W. Sorociak
B. Grzesik
J. Bzówka
P. Mieczkowski
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Abstract

Throughout the world, considerable quantities of water treatment sludge (WTS) and sewage sludge (SS) are produced as waste. This study assessed in the laboratory, the possibility to use both waste products when they are incorporated as filler at 1% with relation to the total mass of a hot mix asphalt - HMA. To this end, both waste products were initially reduced to ash through a calcination process. Resistance tests under monotonic load (Marshall and indirect tension tests), and cyclic load (resilient modulus test) were applied on mixes that contained WTS and SS. Besides, moisture damage (modified Lotmman test), and abrasion (Cantabro) resistance were assessed. An analysis of variance (ANOVA) test was performed in order to verify if the results are statically equal or not to those of the control HMA. As a general conclusion, it is reported that both materials show a resistance increase under monotonic load and higher stiffness under cyclic load (cohesion) when they are incorporated into the mix as filler despite the fact that the asphalt content used was less than the control mix. However, some problems are observed associated with moisture damage resistance, and friction wear (adherence).

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Authors and Affiliations

J.G. Bastidas-Martínez
J. Camapum De Carvalho
L.C. Lucena
M.M. Farias
H.A. Rondón-Quintana
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Abstract

Creep compliance of the hot-mix asphalt (HMA) is a primary input of the current pavement thermal cracking prediction model used in the US. This paper discusses a process of training an Artificial Neural Network (ANN) to correlate the creep compliance values obtained from the Indirect Tension (IDT) with similar values obtained on small HMA beams from the Bending Beam Rheometer (BBR). In addition, ANNs are also trained to predict HMA creep compliance from the creep compliance of asphalt binder and vice versa using the BBR setup. All trained ANNs exhibited a very high correlation of 97 to 99 percent between predicted and measured values. The binder creep compliance functions built on the ANN-predicted discrete values also exhibited a good correlation when compared with the laboratory experiments. However, the simulation of trained ANNs on the independent dataset produced a significant deviation from the measured values which was most likely caused by the differences in material composition, such as aggregate type and gradation, presence of recycled additives, and binder type.

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Authors and Affiliations

A. Zofka
I. Yut
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Abstract

Iron production’s waste materials include significant quantities of blast furnace slag (BFS) which could potentially be used as a substitute for natural aggregates in hot mix asphalt (HMA) used in highway projects. Although many of properties of slag are interesting, its porosity and absorption rate would lead to greater consumption of asphalt. For this study, a Portland cement (PC) paste was used to reduce the porosity of a BFS. This PC treated BFS (called BFS-C) was then used in an HMA to replace the coarse fraction of a natural aggregate. Marshall, Indirect Tensile Strength (ITS), resilient modulus and Cantabro tests were then carried out on different HMA mixtures that included BFS-C. Using BFS-C, HMA’s resistance under monotonic loading, stiffness under cyclic loading, and resistance to moisture damage increased remarkably. In addition, the Cantabro abrasion resistance of BFS-C improved was better than that of the HMA mixture produced with untreated BFS.

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Authors and Affiliations

H.A. Rondón-Quintana
J.C. Ruge-Cardenas
J.G. Bastidas-Martínez

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