Thixotropic evaluation of a highly-workable and a flowable concrete made with Rice Husk Ash

Thixotropic behaviour of a Highly-Workable Concrete (HWC) and a Flowable Concrete (FC) containing varying volumetric dosages (10%, 15%, and 20%) of Rice Husk Ash (RHA) has been investigated using a coaxial cylinder concrete rheometer. The parameters to evaluate the thixotropic behaviour were RHA dosage and grade of concrete. The experiments showed that concrete exhibits a high degree of thixotropy when proportioned with a binary binder containing RHA. The influence of RHA on thixotropy was more pronounced in the HWC than in the FC. The measured thixotropic indices for the HWC, i.e., initial peak stress, thixotropic index, structuration rate, structure parameter, and reduction in apparent viscosity, increased with the increase in RHA dosage, compared to the control concrete. However, the influence of RHA in the case of the FC on all the thixotropic parameters was not significant. As the concrete grade increased from M -30 to M -50 in the HWC, thixotropic parameters in the RHA blended concrete increased significantly compared to the control concrete.