PERFORMANCE EVALUATION OF SCORIA AS PARTIAL REPLACEMENT OF FINE AGGREGATE AND RECYCLED WASTE HOLLOW CONCRETE BLOCK (WHCB) AS FILLER MINERALS ON HOT MIX ASPHALT CONCRETE

Abstract

Asphalt concrete pavement is one of the most durable and comfortable type of road. To construct such like road consumes a large amount of crushed aggregate and it leads scarcity of materials and expensiveness. Hence, it required to searching the optional materials that can be substituted for and used in hot mix asphalt (HMA) production. The aim of this study is to evaluate the suitability of scoria and recycled WHCB as partial replacement of fine aggregate and filler minerals on asphalt concrete mix. To meet the objectives of the study the physical properties of materials were studied separately and the results obtained were satisfied the specification requirements except for scoria water absorption. In combination test with fine aggregate the result were also satisfied the absorption requirement. The effects of scoria and recycled WHCB modified mix were conducted separately and blending of them. The result shows modified mix requires a little more bitumen than control mix. The optimum bitumen content of control mix were 4.85%, while at 20% scoria replacement resulted as 5.1%. In marshal mix, incremental scoria levels from 10% to 40% were conducted, and at 20% replacement provides good result on all parameters. Similarly, the result of test adopted by using WHCB of 25%, 50% and 75% in mixture shows, it were satisfied all requirements up to 50% and decrease at 75% replacement. The combination mixtures of these two materials were provided good result using 20% scoria with 25% WHCB replacement. The ITS and TSR were performed and unmodified HMA concrete was 7.87% higher at dry conditions and 14.27% at wet conditions than modified mix. The Tensile strength ratios (TSR) of modified and unmodified mixtures were 76.34% and 81.96%, respectively. Therefore it was meet the minimum requirement that is 75% and can be used in asphalt pavement production. In cost analysis also the replacement of these materials would be save 2.412% of total project cost and which is valuable in economic advantages. Therefore the study concludes that the replacement of scoria at 20% and recycled WHCB at 25% in asphalt concrete mix can provide good result and better to use in HMA concrete production. Also utilization of these materials have valuable cost reduction of natural crushed aggregate.