磷酸镁水泥制备试验研究

基于水工建筑物的应急抢险与快速修补加固处理的需要,运用常规的水泥凝结时间、强度等基本性能试验,研究各材料组成对磷酸镁水泥性能的影响,确定磷酸镁水泥配方,并对不同粒径砂土的磷酸镁水泥砂浆水胶比、养护条件、强度等进行了试验研究。结果表明,硼砂是磷酸镁水泥的有效缓凝剂;氧化镁细度对水泥性能有明显影响,氧化镁越细水泥早期强度越高,但细度过细凝结时间将难以满足施工要求;磷酸镁水泥配方为:P/M值1∶3,硼砂掺量10%,氧化镁细度宜为195 m~2/kg左右;磷酸镁水泥砂浆抗压强度与胶水比具有线性相关性,与龄期呈对数关系;水中养护与标准养护相比,抗压强度降低约6%～27%,磷酸盐水泥在长期水下环境中的适用性需论证。研究成果可为水工建筑物的应急抢险与快速修补加固处理提供参考和依据。

Experimental study on preparation of magnesium phosphate cement

Based on the needs of emergency rescue and rapid reinforcement of hydraulic structures，with using the basic performance tests on cement setting time，strength，etc． ，the influence of each material on the performance of magnesium phosphate cement is studied to determine the fomula，meanwhile the relevant tests are conducted to study the water to binder ratio，curing condition，strength，etc． ，of magnesium phosphate cement mortars with different particle sizes of sand． The results show that borax is an effective retarder for magnesium phosphate cement． And the fineness of magnesium oxide has a significant influence on the cement performance，the finer the magnesium oxide，the higher the early strength of cement; however，the setting time will be difficult to meet the construction requirements if the fineness is too fine． The fomula of magnesium phosphate cement is determined as: P /M value is 1 ∶ 3，the borax content is 10%，the magnesium oxide fineness is 195 m2 / kg． The compressive strength of the magnesium phosphate cement mortar has a linear correlation with the binder to water ratio，and has a logarithmic relationship with the age． Compared with the samples under the standard curing condition，the compressive strength of samples under the water curing condition is reduced by about 6% ～ 27%; therefore，the applicability of magnesium phosphate cement under the long-term underwater condidtion needs to be demonstrated． The above study results can provide a reference and basis for emergency rescue and rapid reinforcement of hydraulic structures．