An investigation of rheological and mechanical properties of cement base grout mixed with rice husk ash (RHA)

This thesis investigated the fluidity, rheological, mechanical and stability properties of the cement based grout mixed with rice husk ash (RHA). The experimental program consisted of fifteen different mixture and 135 soilcretes samples having 5%, 10%, 20%, and 30% RHA content and three different water to binder ratios (w/b = 0.75%, 1.00%, and 1.25%). Workability properties, plastic viscosity, apparent viscosity, and the yield stress of the mixtures were determined in the first part of the study. And then, unconfined compressive strength (UCS), bleeding and failure criteria of the soilcrete samples prepared like first part of the study at similar proportions of RHA and w/b ratios. In order to obtain soilcrete samples, this grout mixtures were mixed with clay at 20% proportion by mass. 3,7 and 28 day air curing program was applied to all samples. The compressive strength, elastic modulus, stability parameters were investigated. Test results showed that increasing replacement level for the RHA amount increases marsh cone flow time, plate cohesion, plastic and apparent viscosity, and the yield stress, but also decreases mini slump diameter. Shear thickening and pseudo-plastic behavior was observed for high RHA content for w/b ratios greater than 1.00. All UCS values are greater than 1 Mpa and all bleeding values obtained are lower than 5%.