蛋壳粉对偏高岭土—水泥水化和强度的影响

Effect of eggshell powder and metakaolin on hydration and strength of cement

为探究蛋壳粉(ESP)对偏高岭土(MK)—水泥体系的影响,将蛋壳粉与偏高岭土以不同的质量比取代水泥制备试件,对试件的强度结果以及水化产物进行分析。结果表明,ESP与MK分别取代10%水泥的试件,与单掺20%MK的水泥相比,各个龄期强度除3 d强度降幅较大外,7、28 d强度都仅有略微的降低。与对照组PC相比3 d强度降低过大,7 d强度略微降低,28 d强度略高于PC;ESP和MK分别取代10%和20%水泥的试件,与单掺30%MK相比,各个龄期强度除3 d强度略微降低外,7、28 d强度大致相同,与PC相比有类似结果。所有复掺试样中,ESP和MK的分别取代5%和20%水泥试件抗压强度结果最优,与PC相比提升了约15%。偏高岭土-水泥体系中加入蛋壳粉可增加浆体溶液中碳酸根离子的浓度,与偏高岭土中的铝相结合生成碳酸铝盐,可增加水泥水化产物体积,从而提高水泥后期强度的发展。

To explore the composite effect of eggshell powder(ESP)and metakaolin(MK)in cement,eggshell powder and metakaolin were compounded to replace cement with different mass ratios.The effect of compound mixing eggshell powder and metakaolin on cement strength was studied.The results show that ESP and MK replace 20%cement with 1∶1.Compared with cement with 20%MK,the strength at each age decreases slightly at 7 and 28 days,except that the strength at 3 days decreases greatly.Compared with PC,3 d strength decreased too much,7 d strength decreased slightly,and 28 d strength was slightly higher than PC.When ESP and MK replace 30%cement with 1∶2,compared with cement with 30%MK,the 3 d strength decreases slightly,and the 7 d and 28 d strength is basically the same.Compared with PC,the 3 d strength is lower,the 7 d strength is basically the same,the 28 d compressive strength is slightly higher than PC,and the flexural strength is significantly improved.Among all the mixed samples,the composite strength of ESP and MK with 1∶4 instead of 25%cement is the best,and the compressive strength is increased by about 15%compared with PC.Adding eggshell powder to metakaolin cement system can increase the concentration of carbonate ion in slurry solution,combine with aluminum in metakaolin to form aluminum carbonate,and increase the volume of cement hydration products,so as to improve the development of later strength of cement.