In the chemical modification of fluoropagsum, the setting time, strength and effect of different kinds of admixtures on fluoropagsum after milling were studied
The degree of frost. The results show that the improvement effect of a single type of admixture on the properties of fluoropagsum is not comprehensive
There are limitations. Among them, the addition of A small amount of admixture A can obviously shorten the setting time of fluoropgypsum, improve the early strength,
But will cause the occurrence of frost phenomenon; The addition of sodium carbonate can promote the hydration and hardening of fluoropgypsum and stimulate the strength of fluoropgypsum.
But its dosage is large and its effect is small. A large number of admixture B can accelerate the hardening process of fluoropgypsum and improve the properties of fluoropgypsum
The late strength can effectively avoid the occurrence of frost phenomenon, but the strength of the activated fluoropgypsum is limited. The addition of sodium nitrite can be
It can improve the condensation property of fluoropgypsum well, but it will cause specimen expansion, cracking, warping and other phenomena, fluoropgypsum volume
Poor stability.
The effects of different kinds of admixtures on the properties of fluoropaggy after milling were studied and the best modification method of fluoropaggy was determined. The results show that the addition of admixture B can inhibit the frost phenomenon of fluoropgypsum/admixture A composite cementitious material, and the addition of recycled gypsum can further shorten the setting time of fluoropgypsum/admixture A/ admixture B composite cementitious material. The test determined that the best method of fluoropaggy composite modification is: after fluoropaggy powder treatment for 20min, adding 1.0% admixture A, 0.7% admixture B, 1.5% recycled gypsum, then the initial setting time of modified fluoropaggy.
It is 4.4h, the final setting time is 5.5h, the flexural strength of 7d is 7.6MPa, and the compressive strength is 39MPa, which can meet the requirements of fluoropgypsum construction
Requirements for resource utilization of materials.
