Research Of Properties Modification And Applications Of Sulphoaluminate Cement

The performance of general purpose Portland cement can satisfy the need of the common engineering construction, but it can not be applied in rapid construction engineering, such as quick-repair, emergency treatment and leakage-preventing engineering. Recently, the research and making of sulphoaluminate cement have rapidly developed; the cement has the properties of early strength, high strength, anti-frost, impermeability, and low alkality and so on. Sulphoaluminate cement sets rapidly, it is not avail to construct for its setting time (such as repair and grouting engineering), but in other engineering (such as leakage-preventing engineering), it requires cement has rapid setting and high hour strength. In order to exert the potential and widen the application of sulphoaluminate cement, it is needed to appropriately adjust the cement's setting time and other properties according to the characters of the engineering.Firstly, this paper studied the effect of Portland cement's dosage on OPC-SAC blended cement's properties. Then the effects of different chemical admixtures on properties of SAC were discussed. Using XRD, SEM and microcalorimeter tested the effect of OPC, retarder A and accelerator B on SAC's hydration. From the results some blending ratios of sulphoaluminate cement and Portland cement were found that can be applied in quick-repair and consolidation engineering, and admixtures which can commendably adjust the properties of the sulphoaluminate cement.Result and analysis of the experiments showed that the hydration will be quickened and strength decreased when the sulphoaluminate cement blended with Portland cement. When the dosage of OPC is 10%~20% of blended cement, the setting time is remarkably shortened, early flexural strength appreciably increased, late strength appreciably decreased, and the properties of strength and shrinkage are improved under the drying curing condition; when the dosage of OPC is 40%~50% of blended cement, the cement flash sets and strength obviously decreased. The results of hydration heat, XRD and SEM showed that OPC blended with SAC, due to the cement's alkalinity elevated, hydration heat flow advances, hydration products form quickly, and there is not new hydration products formed. FDN is compatible with SAC; retarder A is not steady when used inSAC, but it can increase the late strength of SAC; appropriate dosage of B can obviously shorten the set of SAC, and increase the hour strength; the matters that retarder A is not steady and decreases hour strength can be resolved by mixing A and accelerator into SAC, B and NS are the best in all accelerators. Polymer emulsoid powders RE5040N decreases the compressive strength of SAC, increases tesile and cross bending strength, decreases brashness, and improves adhesive force.On the basis of above studies, retarding and accelerating waterproof and leakage-preventing materials, anchor grouting and second grouting super high early strength grouting materials were developed, moreover, physical and mechanical performance were tested. The waterproof and leakage-preventing materials satisfy the requirements of JC900-2002 (inorganic waterproof and leakage-preventing materials). The quick gurouting and anchor grouting materials have properties of self- leveling, super early strength, high strength, tiny-expansile, and so on. The super early strength of this material maybe related with the mass form of AFt when the OPC-SAC blended cement early hydrates.