Dynamic and Static Characterization of Polypropylene Fiber-Reinforced Dune Sand

Dune sands characterized by a susceptibility to large deformations can be a useful pavement construction material if reinforced or treated with cement. Sand can be easily reinforced with synthetic fibers to increase its stiffness and load-carrying capacity. This study was undertaken to investigate the resilient behavior of polypropylene fiber-reinforced sand. Triaxial, California bearing ratio (CBR), and resilient modulus tests were conducted on fiber-reinforced sand as well as unreinforced sand, and the results compared. The optimum fiber content was found to be 0.4% by weight. The triaxial shear strength of the fiber-reinforced sand specimens revealed that there were two modes of failure, fiber-sand bond failure and fiber failure, and the internal friction angle depended on the mode of failure. Synthetic fiber-reinforced sand has greater CBR values than those of unreinforced sand. The effect of fiber reinforcement on the resilient modulus, MR, values was investigated in terms of resilient modulus model parameters. In general, the model parameters revealed a decreasing effect of both the deviator and confining stresses on the MR values up to 0.2 to 0.4% fiber content. The permanent deformation of sand specimens was reduced by the addition of fibers, and the permanent deformation decreased as fiber content increased. </jats:p

UTILIZATION OF CEMENT WASTE IN ASPHALT CONCRETE

Cement Kiln Dust (CKD) was added as a filler in asphalt concrete mixes. It was found that adding CKD to asphalt concrete mixes as a filler (5 and 7% of aggregate) produced acceptable mixes at 4% air voids but the optimum asphalt content was lower for the 3 and 5% CKD and higher for 7% CKD compared with conventional mineral filler (limestone dust

Factors Affecting Resilient Behavior of Subgrade Soils in Saudi Arabia

This paper presents a study of the effect of relative density and moisture content on the resilient behavior of subgrade soils in Saudi Arabia. Thirteen representative soil samples, representing subgrade soils from all over the Kingdom, were tested at two different relative densities (93% and 96%) and the corresponding moisture contents on the compaction curves in addition to the optimum moisture content and maximum density. The results show that the resilient behavior depends on soil type (fine grained or granular) as well as moisture content and relative density. The study shows that both moisture content and relative density governs the effect of deviator and confining stresses on MR behavior. The study emphasized the importance of using a model that describes correctly the dependency of MR on both confining and deviator stresses. Keywords: resilient modulus, subgrade soil, modelin