Experimental Study on the Effect of Adding Polypropylene Fibers on Soil Stabilized by Cement and Zeolite Replacement

Soil properties improvement involves a variety of approaches. Among them, the addition of specific materials to the soil has been widely adopted in the literature. Although cement impact on environment is negative, it has been widely-used in many construction projects. Therefore, the main purpose of this research is to find suitable alternative methods to decrease cement usage, one of which is the addition of polypropylene fibers and zeolite. 126 types of unconfined compression tests with different ingredients were carried out with the aim of decreasing cement usage and improving soil properties. Two types of sandy soil were adopted in this study, i.e., SP and SW soil. They were improved by 4% of cement, 0, 0.25, 0.5, 0.75, and 1% of polypropylene fibers with random distribution, and 0, 10, 30, 50% of zeolite were used during curing periods of 7, 14, 28 days. According to the compaction test results, with the addition of 0.5% polypropylene to the SW soil, and 1% to SP soil, the value of optimum moisture increases, and then decreases. On the other hand, the addition of polypropylene fibers resulted in decrease of the special dry weight of both type of soils. It also revealed the optimum percentage of zeolite and polypropylene fibers to the SW soil are 30% and %0.5, respectively, while this values in the SP soils are 10% and %0.75, respectively. The proper adoption of zeolite and polypropylene in cement led to increase in unconfined compression tests as well as elastic deformation strength.