微量磷酸盐对蒸养混凝土强度增效作用的影响

研究了微掺量(0.05%之内)磷酸盐对蒸养混凝土强度的影响,对比不同掺量氯化钙和硫酸钠,并进行微观分析.结果表明,当磷酸盐掺量为0%~0.05%时,随磷酸盐掺量的增加,蒸养混凝土强度先升高后降低.当掺量为0.01%时,脱模强度提高14.7%,28 d强度提高15.3%,当掺量为0.05%时,对蒸养混凝土强度增长不利,微掺量氯化钙与硫酸钠对蒸养混凝土强度基本无影响.在0.01%掺量下磷酸盐能促进水泥地水化作用,同时使得水化产物晶体形貌生长规整和分布更加均匀,有利于强度增长;当掺量为0.05%时,磷酸盐会阻碍水泥水化,对蒸养混凝土强度增长不利.

Effect of Microdosage Phosphate on Enhanced of the Strength of Steam-Curing Concrete

Effects of microdosage phosphate (≤0.05%) on the compressive strength of steam-curing concrete were investigated, the effects of the different dosage of CaCl2 and Na2SO4 on the compressive strength of steam-curing concrete were compared with mircodosage phosphate, and the microstructure of samples with different phosphate was also analyzed.The results show that the compressive strength of steam-curing concrete increases and then decreases with the dosage of phosphate increasing.In the dosage of 0.01%, the early compressive strength increases 14.7%, 28 d strength increased 15.3%, in the dosage of 0.05%, it is harmful for the strength.The microdosage CaCl2 and Na2SO4 have no influence on the compressive strength of steam curing concrete.Phosphate can promote the hydration of cementand make the cement hydration crystal growth regularly and well-distributed in the dosage of 0.01%, which is benefit to the development of the strength;In the dosage of 0.05%, phosphate have an ability to delay cement hydration, it is most detrimental to the development of steam-curing concrete strength.