Experimental investigation of expansion behavior and uniaxial compression mechanical properties of expansive grout under different constraint conditions

Traditional grouting technology only provides a bonding effect to surrounding rock fissures. Here, a new expansive grout was prepared using a high-efficiency soundless crush agent as the expansion source to provide an extrusion effect in the early stage of hydration development. Expansion and uniaxial compressive strength (UCS) tests under three expansion constraint conditions were designed to analyze the expansion behavior and mechanical properties of the expansive grout. The results show that the expansion development of the grout mostly occurred within 24–72 h after final setting; greater restrictions in the constraint conditions produced a smaller volume expansion ratio and a greater compressive strength. The volume expansion ratio and UCS of expansive grout are considerable; volume expansion occurs rapidly, while the strength increases, indicating good application prospects in grouting reinforcement engineering.