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以石灰石微粉(LS)为参照,研究了20、40℃和60℃养护时10%和30%掺量白云石微粉(DM)对水泥砂浆强度的影响,并采用压汞法(MIP)研究了混合水泥砂浆的孔结构。结果表明:20℃和40℃时,LS优于DM促进早期强度发展,但两者差异随掺量增加和龄期延长而减小。提高温度到60℃,对DM砂浆各龄期强度的促进效应均比对LS体系更为显著,且掺量愈大,两者对温度效应的差异愈明显。3种养护温度下,DM与LS的掺入均增加砂浆孔隙率,且掺量愈大孔隙率愈大。10%掺量时,DM与LS对孔径分布影响不大,而30%掺量时两者均明显粗化孔径。与LS相比,20℃时,DM砂浆孔隙率大于LS砂浆,孔径粗化也更为明显;40℃时,DM砂浆孔隙率近似或小于LS砂浆,两者孔径分布类似;继续提高温度到60℃,DM砂浆孔隙率小于LS砂浆,孔径分布优于LS砂浆,且掺量愈大两者差异愈明显。提高养护温度,对DM砂浆孔结构的劣化效应弱于LS砂浆。DM的化学活性对升高温度的响应强于LS,DM反应生成的水滑石利于降低孔隙率并改善孔径分布,促进水泥砂浆强度发展。
The effects of 10% and 30% dolomite (DM) on the mortar strength were studied by using limestone powder (LS) as a reference. The effects of DM on the mortar strength were studied by using mercury intrusion porosimetry (MIP) Hole structure of mixed cement mortar. The results showed that LS at 20 ℃ and 40 ℃ promoted the development of early strength, but the difference between them decreased with the increasing of the dosage and the prolongation of age. When the temperature is raised to 60 ℃, the promoting effect on the strength of DM mortar is more significant than that on the LS system. The greater the dosage is, the more obvious the difference of the temperature effect is. At the three curing temperatures, the incorporation of DM and LS both increased the mortar porosity, and the greater the dosage, the greater the porosity. When 10%, DM and LS had little effect on the pore size distribution, while both of them were coarsened at 30%. Compared with LS, the porosity of DM mortar is larger than that of LS mortar at 20 ℃, and the pore diameter roughening is more obvious. The porosity of DM mortar is similar to or less than that of LS mortar at 40 ℃, and the pore size distribution is similar. ℃, the porosity of DM mortar is less than that of LS mortar, and the pore size distribution is better than that of LS mortar. The greater the dosage, the more obvious the difference is. Improve the curing temperature, DM mortar pore structure of the deterioration effect is weaker than the LS mortar. The chemical activity of DM is more responsive to elevated temperature than LS. The hydrotalcite produced by DM reaction is conducive to reducing porosity, improving pore size distribution and promoting the development of cement mortar strength.