Water-based drill cuttings, a shale gas extraction waste as supplementary cementitious material and optimization

Abstract

• A method of preparing a novel supplementary cementitious material based on water-based drill cuttings was provided. • A central composite design was conducted to optimize the four factors (calcination temperature, calcination time, replacement ratio, and fineness) for WDC preparation, and optimal values were obtained. • The hardened specimens, prepared with a mixture of standard sand, ordinary Portland cement, and water-based drill cuttings, meet the compressive strength specified in ASTM-618. • The mechanisms of WDC acting in the OPC system were investigated. The water-based drill cuttings, a kind of solid waste from shale gas extraction, are examined for their utility as supplementary cementitious material. After drying, calcining, and grinding, water-based drill cuttings are expected to partially replace ordinary Portland cement for their high calcium silicate and grinding-friendly nature. A central composite design investigated four variables (calcination time, calcination temperature, replacement ratio, and fineness) for their effects on the response (compressive strength). The optimization results suggest that the best product meeting the mechanical criteria and saving energy could be obtained by replacing 10 wt% ordinary Portland cement when controlling the calcination temperature of 830–870 °C, calcination time of 28–32 min, and fineness of sieving is 1600 mesh. The compressive strength was shown to be 39.00 MPa at 7 days, 47.00 MPa at 28 days, and 52.00 MPa at 90 days. Furthermore, the mechanisms of water-based drill cuttings were characterized to confirm the feasibility of supplementary cementitious material by various analytical techniques such as X-ray fluorescence, laser particle size analyzer, simultaneous thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy.