Preparation And Properties Of High Resistance Cement

In this thesis, cement-based materials which modified by pyrophyllite or polymer was studied by usual way and SEM. The main contents are to know what effects of the ratio of pyrophyllite or polymer, such as sodium carboxymethylcellulose(CMC), epoxide resin(EP), polyvinyl acetate(PVA), to volume resistivity of cement, and to study the mechanics performance and durability of cement-based material.Experimentation results indicated that when the admixture was mixed into cement, the volume resistivities of the composite cement were improved in various degrees, especially the composite cement materials which were modified by EP or PVA were good. For compressive strength, the28-day compressive strength of the samples mixed with EP increased most significantly; the samples mixed with PVA were also better, the intensity at first went up with increase of PVA content and then decreased; when the dosage was2%, compressive strength had the maximum value. The effects to compressive strength of cement composite materials with pyrophyllite or CMC were not obvious. The sulphate-resistance properties were better when calcined pyrophillite, CMC or EP was added.The properties of modified cement materials which were modified by pyrophillite and polymer were also tested. When adding calcined pyrophillite and polymer into cement, samples’volume resistivity, compressive strength and sulphate-resistance were superior to the samples with pyrophillite and polymer. For28-day volume resistivity, the28-day volume resistivities of calcined pyrophyllite/EP/cement and calcined pyrophyllite/PVA/cement were better than pure cement, EP/cement and PVA/cement samples. But there were not observable changes in28-day volume resistivity of calcined pyrophyllite/CMC/cement. For28-day compressive strength, it was not significantly improved, except calcined pyrophyllite/EP/cement system. Only calcined pyrophyllite/EP/cement system, pyrophyllite/PVA/cement system and calcined pyrophyllite/PVA system had good sulfate-resistance properties.Through adding pyrophyllite power and polymer to cement materials and using their synthesis advantages, multifunction cement materials can be empoldered. It has positive meaning in developing new type cement-based functional composites and enlarging application area of pyrophyllite.