Effect of water immersion on the AC-WC mixture utilizing elastomeric modified asphalt to compressive strength, elastic modulus and durability

Abstract

Indonesia has relatively high rainfall with a long duration of rain. It can result in a flood on the surface of the road. A flood can reduce the strength of materials from the asphalt mixture and cut the life of the road plan. Therefore, it is necessary to conduct a study that can measure the durability level of the asphalt material mixture on the surface layer of the road to the flood water bath. The study used an Asphalt Concrete-Wearing Course (AC-WC) mixture with Elastomeric Modified Asphalt (EMA), and an Upper Limit (UL), Middle Range (MR), and Lower Limit (LL) gradation based on specification. The Optimum Bitumen Content (OBC) value was obtained from each gradation by applying the Marshall test. The value of the OBC was used to create specimens that had a diameter of 3 inches and a height of 6 inches, and they were using an Unconfined Compression Strength (UCS) test. This study measures the durability of compressive strength and elastic modulus from a mixture of flood water immersion for 1, 2, 4, and 7 days. To calculate the durability using Retained Strength Index (RSI), First Durability Index (r), and Second Durability Index (a). The results showed that there was a decrease in the compressive strength of the mixture on gradations of UL, MR, and LL on days 1, 2, 4, and 7. It meant that the longer the immersion time more reduced the compressive strength of the mixture. The UL-gradedraded mixture had the best durability when it was compared to the MR and LL gradations up to the 7th-day immersion, with an RSI of 91.19%, (r) of 7.44%, and (a) of 6.93%. At the same time, in the elastic modulus of the mixture, there was no significant effect on the duration of immersion because it had a fluctuating value of the elastic modulus to the duration of immersion.