海藻酸钠对磷酸钾镁水泥水化性能的影响

Effect of Sodium Alginate on Hydration Performance of Magnesium Potassium Phosphate Cement

磷酸镁水泥是一种新型快硬高强的胶凝材料,但凝结速度过快会导致其应用受限,利用缓凝剂可拓展其应用范围。本文以磷酸二氢钾和重烧氧化镁为原料制备磷酸钾镁水泥,研究一种具有潜在缓凝效果的缓凝剂——海藻酸钠对磷酸钾镁水泥凝结时间、力学性能、微观结构的影响。研究结果显示:掺入海藻酸钠对磷酸钾镁水泥有较好的缓凝效果,其中浓度(质量分数)为1%的海藻酸钠溶液缓凝效果最佳,可将磷酸钾镁水泥的凝结时间最高延长至35min;掺入浓度为1%的海藻酸钠在水化早期可提高磷酸钾镁水泥的强度,比未掺时的强度最多提高了15.69%,但水化后期海藻酸钠的掺入对强度产生不利影响。

Magnesium potassium phosphate cement(MKPC)is a new fast hardening and high strength cementitious material.However,its application is greatly limited due to its fast setting speed.Therefore,more retarders need to be studied to improve its application prospect.MKPC was prepared with potassium dihydrogen phosphate and calcined magnesium oxide as raw materials.This paper studies the effects of sodium alginate on the setting time,mechanical properties and microstructure of MKPC.The results show that the sodium alginate has a good retarding effect on MKPC.Sodium alginate with concentration(mass fraction)of 1%has the best retarding effect,which can prolong the setting time of MKPC to 35 min;and 1%sodium alginate will improve the strength in the early stage,the strength is increased by 15.69%at most compared with that without doping.However,each concentration of sodium alginate in the later stage has an adverse effect on the strength.