Review of The Literature on The Use of Rice Husk Ash As a Sustainable Filler Substitute in Hot Rubber Asphalt Mixtures for Road Pavements' Wearing Course

The province of South Sumatra has a rice cultivation area of 496,241.65 hectares and the largest production of 2.55 million tonnes on the island of Sumatra in Indonesia, which has a lot of land for rice cultivation with a harvested area of about 10.41 million hectares. However, because rice husks have low protein content and high ash content, most of it is burned, buried or dumped into water as garbage, which negatively affects local ecosystems and causes air and water pollution. With increasing pollution and the rising cost of building materials, several scientists have been looking at this area of study to find ways to harness the potential of rice husk ash. Amorphous silica with high purity is the best silica that can be found. Silica has been studied as a potential additive for hot asphalt mixtures to reduce air gaps and increase indirect tensile strength and indirect tensile modulus. Silica can also make asphalt more cohesive and viscous, improving its performance at high temperatures. It can also make asphalt more resistant to oxidative ageing and improve its performance at higher temperatures. Especially in regions where a lot of rice husk waste is generated, rice husk ash can therefore be used as an alternative to conventional mineral fillers in hot asphalt mixes.