水灰比和偏高岭土掺量对硫铝酸盐水泥基材料性能的影响

Effects of Water-cement Ratio and Metakaolin Blending Ratio on the Performance of Sulphoaluminate Cement-based Material

为了研究水灰比和偏高岭土掺量对硫酸铝盐水泥的流动度、收缩率和力学性能的影响,以龙门石窟裂隙防渗的灌浆工程为例,开展流动性试验、力学性能试验及干缩性能试验。结果表明:硫铝酸盐水泥初始流动度大小与水灰比、偏高岭土掺量均成正比;水灰比越高,微膨胀率越低,甚至出现一定收缩,整体上膨胀率随偏高岭土掺量增大而变大;抗压强度大小与水灰比、偏高岭土掺量均成反比;7 d的抗折强度随偏高岭土掺量增大而减小,养护28 d的抗折强度恰恰相反;抗折强度随水灰比的增大而减小,且回落幅度相对较大;黏结强度随水灰比先增大后减小,随偏高岭土掺量增加,黏结强度整体上有所增加,在水灰比为0.5时,出现1个峰值。试验结果可为龙门石窟的现场灌浆试验提供理论依据,也可为同类石质文物的灌浆修复研究提供参考。

To study the influences of water-cement ratio and metakaolin blending ratio on the fluidity,shrinkage and mechanical properties of sulphoaluminate cement,we take Longmen Grottoes as an example,and carry out tests on fluidity,mechanical properties and dry shrinkage property. The results show that,firstly,the initial fluidity of sulphoaluminate cement is proportional to water-cement ratio and metakaolin blending ratio; secondly,the higher water-cement ratio is,the lower microexpansion rate is,even with a little contraction. In general,expansion rate increases with metakaolin blending ratio; compressive strength is inversely proportional to water-cement ratio and metakaolin blending ratio; the flexural strength of specimens cured for 7 days decreases with the increasing metakaolin blending ratio,while the flexural strength of specimens cured for 28 days is on the contrary; flexural strength decreases with the increasing water-cement ratio,and the decline rate is relatively large; bonding strength increases first and then decreases with the increasing water-cement ratio; while with increasing metakaolin blending ratio,bonding strength increases overall,and in particular,peak value occurs under water-cement ratio of 0. 5. The experimental results provide theoretical basis for the field grouting test in Longmen Grottoes,and also provide reference for grouting repair in similar stone cultural relics.