Estudo do comportamento resiliente de um solo laterítico estabilizado com ácido fosfórico e cinza da casca de arroz

Abstract

In view of the need to expand the national road network, it is interesting to use local soils, in the structural layers of a pavement, thus reducing transportation costs. Sometimes, these soils do not have adequate support capacity to enable their use in base and sub-base layers, with chemical and mechanical stabilization being an alternative for soil improvement. This work aimed to study the stabilization potential of a lateritic soil, from the municipality of Cruz Alta / RS. For stabilization it was used the addition of rice husk ash (CCA) and phosphoric acid (H3PO4). H3PO4 is a product widely used by the food and pharmaceutical industry, in the road sector, it has been the object of study with presentation of good results as a stabilizing additive for tropical soils. CCA is a residue from the rice processing industries, produced on a large scale in the state of RS. This by-product does not have waste management, and its use in the paving area is a potential alternative to reduce environmental impacts, presenting a possibility of depositing this material. In the present study, different levels of CCA and H3PO4 were adopted in samples compacted in the intermediate and modified energy and subsequently subjected to analyzes and tests in order to identify the variations generated as a result of the additions. To verify the mechanical performance, tests of simple compressive strength and resilience module were performed at different curing ages. X-ray diffraction and scanning electron microscopy analyzes were performed, allowing to distinguish the mineralogical and morphological modifications that could justify the resistance gain obtained through stabilization. The results show a potential for stabilization of the lateritic soil in question, through the addition of CCA and H3PO4. Data on resilient performance were incorporated into the National Dimensioning Method (MeDiNa) to perform mechanistic analyzes. In view of such analyzes, a reduction in the percentage of cracked area of the coating was observed, related to fatigue, using the stabilized soil as a subgrade compared to the soil in its natural state, leading to the conclusion that the stabilization of soils makes its use feasible. in the structural layers of pavements.