Research on the mechanical properties of marine soft clay solidified with waste tile powder-calcium carbide residue geopolymer under freeze-thaw cycles.

Based on the demand of marine soft clay treatment, it is still urgent to seek green cementitious materials. Meanwhile, knowledge gaps exist regarding the application of waste tile powder (WTP)-calcium carbide residue (CCR) geopolymer into marine soft clay. This research explores the mechanical properties and freeze-thaw durability of WTP-clay-CCR system. Experimental results of unconfined compressive strength demonstrate that the strength is 1832.77 kPa after the incorporation of 13% CCR and 15% WTP. However, it is reduced to 474.69 kPa after 4 freeze-thaw cycles. The stability index (SI) is 0.422 after 2 freeze-thaw cycles but it is improved after the incorporation of CCR and WTP. The strength calculation model containing freeze-thaw cycles is proposed. The failure strain of sample is 1.0-2.0%. The peak strain energy and secant modulus are 18.53 kJ/m and 138.44 MPa after the incorporation of 13% CCR and 18% WTP. Finally, the pore characteristics and microstructure are revealed by scanning electron microscope and mercury intrusion porosimetry tests. The stabilization and freeze-thaw mechanism are analyzed. It reveals that the pore filling, gelling material and ion exchange are responsible for the mechanical property improvement. The micro-cracks formation and cracks development result in strength reduction of CCR-WTP-clay under freeze-thaw cycles.