白泥掺量对碱矿渣/白泥砂浆干燥收缩的影响

Effect of lime mud content on drying shrinkage of alkali slag/lime mud mortar

为了高效利用造纸工业固废白泥,以硅酸钾和碳酸钾为复合激发剂,白泥和矿渣为复合前驱体,研究不同白泥掺量对碱矿渣/白泥砂浆(ALM)干燥收缩的影响,并通过X射线衍射分析、热重-微商热重分析和压汞法解释其机理。结果表明:随着白泥掺量的增大,ALM的水化硅酸钙凝胶(C-(A-)S-H)量减少,类水滑石量保持不变,文石、球霰石和方解石量增多,凝胶孔(3.12~10 nm)和中孔(10~50 nm)减少,大孔(>50 nm)增加,ALM吸水率增大,水分损失率增大,名义晶胶比增大,ALM的抗压强度和干燥收缩降低。白泥掺量为20.0%的ALM具有较好的28 d抗压强度和较低的干燥收缩。

In order to efficiently use lime mud,which is a kind of industrial solid waste from paper industry solid waste,the effect of different lime mud content on the drying shrinkage of alkali-activated slag/lime mud mortar(ALM)was studied using potassium silicate and potassium carbonate as composite activators,lime mud and slag as composite precursors,respectively.The mechanism was investigated by X-ray diffraction,thermogravimetry-derivative thermogravimetry,and mercury intrusion porosimetry.The results showed that the amount of C-(A-)S-H gel of ALM decreased with the increasing of lime mud content,and the amount of hydrotalcite remains unchanged.Additionally,the amounts of aragonite,vaterite and calcite was also increased.However,the gel pore(3.12-10 nm)and mesopore(10-50 nm)decreased with the macropore(>50 nm)increasing.Meanwhile,the water absorption of ALM,the water loss rate,and the nominal crystal-binder ratio were all increased.The compressive strength and drying shrinkage of ALM decreased.ALM with lime mud content of 20%possessed satisfactory 28-day compressive strength and drying shrinkage.