Performance of marginal sand improved with wastewater sludge ash and polypropylene fiber

In recent years, the disposal of sludge ash (SSA) in an environmentally friendly way has become more important due to environmental concerns and public health. Therefore, this study investigates the reusability of SSA as a stabilizer with polypropylene fiber (PF) and poorly-graded sand for stabilization purposes performing California bearing ratio (CBR) and unconfined compressive strength (UCS) tests. Experimental study conducted in this study consists of a preliminary study for the determination of inclusion rates of SSA and an extensive experimental study for the investigation of the improvement in sand due to the addition of SSA and PF. In addition, the testing (CBR and UCS) performances of sand stabilized with SSA and PF have been examined through response surface methodology (RSM) in order to find the optimum potential inclusion rates of SSA and PF for the desired testing (CBR and UCS) performances. Also, the effect of the addition of SSA and PF on the strain performances of a pavement structure has been investigated via KENLAYER mechanistic-empirical approach. It is concluded from this thesis study that SSA could be employed with PF and sand in soil stabilization applications.