丙烯酰胺改性粉煤灰聚合增韧注浆材料研究OA北大核心CSTPCD

Efficiently controlling the water inflow(loss)of burnt rocks in the roof of coal mining faces requires grouting reinforcement materials with excellent compressive toughness.Silicate cement-based grouting materials,characterized by low costs,have been extensively applied to grouting reinforcement in coal mines.However,their hardened grout is susceptible to deformation,exhibiting poor toughness.By employing the in-situ polymerization of acrylamide(AM)for toughening,this study investigated the effects of AM,cross-linking agent,initiator,and water-cement ratio on the set-ting time,swelling capacity,compressive strength,and toughness index of the fly ash-based grouting materials.Further-more,the microstructures of the hardened grout were observed using a scanning electron microscope(SEM).Key find-ings are as follows:(1)AM can polymerize in-situ in the fly ash grout to form polyacrylamide(PAM)gel.(2)With AM content of 25%,cross-linking agent content of 0.75%,initiator content of 2.25%,and the water-cement ratio of 0.575,the fly ash-based grouting material exhibits a compressive deformation rate of above 60%,a swelling ratio of 113.43,and a toughness index of 257.92%.(3)Observations of SEM images reveal that the hardened grout of the grouting ma-terial forms an inorganic-organic mosaic network structure,with fly ash particles and PAM gel constituting its rigid framework and flexible network,respectively.The deformation rates derived from the compressive stress-strain curves of the hardened grout generally exceed 40%,suggesting significant plastic deformation characteristics.(4)Engineering experimental results show a maximum flexural toughness deformation rate of up to 25.86%.Overall,the grouting mater-ial developed in this study,with excellent toughness and fluidity,as well as favorable swelling properties in water,can be applied to water seepage and leakage control for coal mine roofs.