An Investigation on Sand Asphalt Sulfur Mixes by using Polymer Modified Binder

To meet the targets of the road development plan of India (1981-2001), about 1 million kilometers of new roads are required to be constructed by the year 2001. To achieve this target, a huge quantity of road aggregates, among other things, are required. Although there is scarcity of coarse aggregates in many areas, sand is available in plenty almost everywhere in India. Keeping in view the deficiencies of the engineering properties of Sand Asphalt paving mixes, a Sand-Asphalt-Sulfur (S-A-S or SAS) mix is likely to satisfy both the criteria of performance and availability of aggregates. Therefore it was decided to carry out the present investigation on SAS mixes using poorly graded medium fine river sand obtained from a nearby river. One of the drawbacks of the SAS mixes is their high air voids content. An effort has been made in this investigation to bring down the voids by replacing a part of the sand by flyash filler, the resulting mix being named as Sand-Asphalt-Flyash-Sulfur (SAFAS) mix. It is expected that the fine particles of the flyash filler will go into the voids to some extent. Possibility of that will improve the strength properties too. In some of the earlier investigations, the effect of varying contents of sulfur and asphalt on the engineering properties of SAS mixes has been studied. However, in doing so, the effect that the varying aggregate contents on the properties of the mixes has been overlooked. This aspect has been taken care of in the present investigation, in that, while varying the asphalt and sulfur contents, the aggregate content has been kept fixed at a particular proportion. In the absence of any specifications regarding the optimum compactive efforts required for SAS mixes, which is less than that for asphalt mixes, it was decided to investigate on the optimum levels of compaction required for SAS and SAFAS mixes. Briefly, the study attempts to cover the following aspects. Effect of varying compactive efforts on Marshall Properties of SAS and SAFAS mixes and selection of an optimum level of compaction, Effect of varying all the constituents namely Sand Asphalt Flyash and Sulfur on Marshall proportion, Indirect tension test, Modulus of resilience, Repeated load indirect tensile test.