Abstract: 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.

Key words: sulphoaluminate cement, water-cement ratio, metakaolin blending ratio, fluidity, mechanical properties