关键词: 毒重石, 凝结时间, 机械强度, 辐射屏蔽

Abstract: Combining witherite′s characteristics，such as high quality，easy-processing，low production cost，absorbing X ray and γ ray etc.，hydraulic cementing material was prepared by using ordinary portland cement clinker as main material， witherite as admixture，and proper amount of gypsum as excipients.Influences of different witherite doping contents on water requirement of normal consistency，setting time，soundness，mechanical strength，and radiation shield performance of the cement were investigated.Results showed that witherite had some retarding effect on the Portland cement clinker.However，the ability of witherite to participate in hydration of cement clinker was so poor that it was basically being an inactive admixture and played a role of filler in cement.Cement based materials with witherite as admixture had certain radiation shield ability， and the radiation shielding effect was more apparent as the content of witherite increased.

Key words: witherite, setting time, mechanical strength, radiation shield