Experimental Study on Influence of Using Urease Enzyme on Stabilized Sandy Soil’s Engineering Property by Zeolite and Sawdust

Soil plays an important role in any structure, so soil improvement has become one of the most essential parts of construction projects. This study investigated influence of  sawdust admixture on inshore sandy soil stabilized by zeolite and urease enzyme. One of the problems that environmental engineers encounter with is accumulating waste materials، sawdust is one of these materials. One way for reducing these side products is reusing them, especially for soil improvement. Sandy soil with uniform granulation (SP) due to it’s incoherence is one of the most problematic kind of soils. Therefore, sawdust with zeolite has been used to improve soil engineering properties and the results have been compared with the effect of calcium carbonate precipitation (CaCO۳) on the soil. Today, by advancement in various sciences and knowledge boundaries elimination in various fields, new and environmentally friendly materials can be used as an alternative method to traditional materials. One of these substances is urease enzymes, which are obtained from natural sources such as Jack Beans  or bacteria’s activity  such as Sporosarcina pasteurii. Samples in this study were made with  ۴, ۸ and ۱۲ percent by weight of zeolite and ۴, ۸ and ۱۲ percent by weight of sawdust and were cured for ۷, ۱۴, ۲۸ and ۴۵ days. According to compaction test results, by increasing zeolite and sawdust’s percentage, optimum moisture content has been increased and maximum dry density decreased. The results of unconfined compression strength (UCS) test showed that the samples with ۴% sawdust, ۸% zeolite and calcite precipitation has about ۹% increase in maximum strength compare with the samples without calcite precipitation and with higher zeolite content. Also, the rupture strain of samples with calcite precipitation was higher than the samples without it.

کلیدواژه ها:

Soil improvement ، Urease enzyme ، Zeolite ، Sawdust ، UCS test