The effect of baghouse fines and mineral fillers on the characteristics of asphalt paving mixtures
Abstract
Asphalt paving mixtures that are to be utilized in paving structures must have properties that will prevent or minimize the following primary distress modes: (1) thermal or shrinkage cracking, (2) fatigue cracking, (3) permanent deformation or rutting, (4) stripping sensitivity. An extensive laboratory study of asphalt paving mixtures containing baghouse fines has been conducted through eleven sets of experimental designs. Marshall size specimens of asphalt paving mixtures with different kinds and amounts of baghouse fines were fabricated using the gyratory testing machine. The following techniques were used to evaluate the influence of the various variables upon mechanical properties, gyratory parameters, resilient modulus, indirect tensile strength, indirect creep, and Hveem stability tests. In addition, in the asphalt paving mixtures, asphalt cement was replaced with baghouse fines in order to maintain a constant volume of asphalt cement plus baghouse fines. The evaluation was conducted under the simulation of plant aging, environmental aging, moisture damage, and traffic densification. The gyratory stability index and gyratory elasto-plastic index can be used to determine the effect of baghouse fines on asphalt paving mixtures during specimen fabrication. The resilient modulus, indirect tensile strength, and Hveem stability decrease significantly with higher amounts of baghouse fines. Artificial aging processes to simulate pavement performance caused an increase in resilient modulus and the indirect tensile strength as well as a reduction in failure tensile strain. Water sensitivity of asphalt paving mixture decreased with increasing amount of asphalt cement or with decreasing baghouse fines/asphalt cement ratio. Densification of asphalt paving mixtures produces higher indirect tensile strength, but it also decreased the resilient modulus. The resilient modulus value was insensitive to the gradation of baghouse fines or mineral fillers, but the indirect tensile strength increased significantly with finer fines or fillers. The results of this study will provide the highway engineer with a better understanding of the effect of different factors on the mechanical properties of hot asphalt paving mixtures with baghouse fines.
Degree
Ph.D.
Advisors
Wood, Purdue University.
Subject Area
Civil engineering
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