Adição de cinza da casca de arroz como alternativa para a estabilização betuminosa em solos argilosos

Abstract

Located in the West Frontier region of Rio Grande do Sul, the city of Alegrete has its economy based on the farming sector, therefore, the lack of quality of the side roads directly interferes on the local economy, since roads in a degradation situation consume more fuel, wear out the vehicles responsible for transporting loads and interfere with the flow of products. In addition, unpaved roads without any type of treatment are more vulnerable to the action of water, wind and the successive passage of truckloads. Among the alternatives for improving these roads, bituminous stabilization is an interesting option, given its simplified execution and positive results, being considered a low-cost ”paving”. However, the application of the technique is limited when dealing with clayey soils, as it presents difficulties in homogenizing the mixture and subsequent compaction on the road. Thereby, rice husk ash is presented as an additive to enable the application of bituminous stabilization in clayey soils, since it has the capacity to reduce soil plasticity and collaborate with the malleability of the mixture, this combined with the fact that there is abundance of the material in the region, since it is a debris generated by rice mills, and has no commercial value. For the present work, the following were used: soil with clayey characteristics, classified as CH and A-7-5, by the Unified Soil Classification System (USCS) and Transportation Research Board (TRB), respectively, cationic asphalt emulsion and rice husk ash without controlled burning temperature. By adding rice husk ash to the mixture of soil and asphalt emulsion, it was possible to obtain a significant improvement in the malleability of the mixture, a fact that consolidates as the greatest gain of the present research, in addition to an increase of 23.3% on simple compressive strength compared to soil stabilized only with asphalt emulsion. In addition, it was observed a gain in resistance to water action of the soil, asphalt emulsion and rice husk ash specimens compared to the other presentations. Keywords: soil stabilization; asphaltic emulsion; rice husk ash; roads; clayey soil.