Use of Ceramic-Industry Wastewater in Sandy Subgrade Stabilization by Deep Mixing Method

Today, with the expansion of transportation, several road construction projects have been implemented in several parts of the world. The aim of this study is to stabilize and test sand using cement and drainage wastewater from the ceramic industry. Use of drained wastewater is to reduce the environmental pollution caused by drainage wastewater and reduced consumption of natural resources. In the first stage, the potential of off-site production by the factories and the advantages of using it were investigated. The optimal mixing plan was then obtained by performing a UCS test on samples that were made with different amounts of cement and wastewater. Other specifications of the desired mixture were: single gravity resistance, elasticity modulus, UCS, loss of resistance in saturation and microscopic structure of the particles. In the final stage, the efficiency of the mixture was studied using numerical modeling by finite element method. According to the results obtained from the experiments, it was found that adding 7.5% cement and 12.5% of dried wastewater, the UCS of sand increase from 0.005 MPa to 0.3 MPa and the sand elasticity modulus increase from MPa 5 to 65MPa. The specimen resistance did not increase significantly since the tenth day, and its saturation caused the resistance of the specimens to be reduced by 50%. The results of EDX and XRF tests revealed that the desired water included heavy metals. in addition use of wastewater reducing the consumption of natural resources, reduces the entry of heavy metals into the environment and urban environments. The level of surface treatment was obtained using sand-shaped modeling; which was considered as a substrate stabilizing element, and other pavement layers. The sum of the summands obtained from the modeling with the maximum allowed values was compared which provided satisfactory results. Finally, the processed sand could be used by deep mixing method to stabilize the subgrade of roads.