Experimental Investigation On Compounding Effects Of Polycarboxylic Type Superplasticizer And Other Chemical Additives

The research and applications of polycarboxylic type superplasticizer are constantly expanding,but as a new superplasticizer,Its composition effects with other chemical admixture were known few that affects the cost and application of polycarboxylic type superplasticizer.In this paper,the composition effect of polycarboxylic type superplasticizer between NSF type superplasticizer,aminosulfonic-based type superplasticizer and aliphatic type superplasticizer were investigated systematically,and the composition effect of polycarboxylic type superplasticizer with some retarders such as sodium tripolyphosphate, pengsha,sodium hexametaphosphate,sodium glutamate,citric acid,lignine sulfoacid calcium,calcium gluconate and sucrose were also studied systematically.The results of the cement paste test about the compounding effects of polycarboxylic type superplasticizer with three other superplasticizers showed that composition results were different to different cement.Generally,the composition effect of polycarboxylic type superplasticizer and NSF type superplasticizer was bad that its inital fluidity and losses reduced violently;The composition effect of polycarboxylic type superplasticizer and aminosulfonic-based type superplasticizer was better than that of NSF type superplasticizer,but it had no cooperative effect;The composition effect of polycarboxylic type superplasticizer and aliphatic type superplasticizer was good,at the same time aliphatic type superplasticizer is very cheap,so it is economic by using the composition of polycarboxylic type superplasticizer and aliphatic type superplasticizer.The results of the cement paste test about the compounding effects of polycarboxylic type superplasticizer and some retarders showed that the composition effect of polycarboxylic type superplasticizer and sodium tripolyphosphate,pengsha and sodium hexametaphosphate were variant due to the different types of cement,for some kinds of cement the cooperative effect was obvious,for some other cement it had no cooperative effect and the fluidity and losses reduced obviously.In one word,the composition effect of polycarboxylic type superplasticizer and sodium glutamate was best,the composition effect of polycarboxylic type superplasticizer and lignine sulfoacid calcium was better,the composition effect of polycarboxylic type superplasticizer and citric acid,calcium gluconate,sucrose were bad.The setting time of P.O42.5R Portland cement(Dunshi)in which adding polycarboxylic type superplasticizer and retarders was studied,The results showed that polycarboxylic type superplasticizer compounding with sodium tripolyphosphate,sodium hexametaphosphate,citric acid,calcium gluconate and sucrose could reduce the setting time,Polycarboxylic type superplasticizer compounding with pengsha,sodium glutamate and lignine sulfoacid calcium could increase the setting time,but the progress test of hydratation showed that compared with only using polycarboxylic type superplasticizer,it compound with sodium glutamate,sodium tripolyphosphate,lignine sulfoacid calcium and calcium gluconate could postpone the temperature apex of hydratation,reduce the hydratation heat of 1d and 3d,while calcium gluconate could reduce temperature apex.Polycarboxylic type superplasticizer compound with retarders could reduce the surface tension of solution,but when the dosage of retarders increased,the range of reduction was not obvious.Compared with only using polycarboxylic type superplasticizer,compositing appropriate retarder could reduce the chlorideion diffusion coefficient of 56d concrete and markedly improve its impermeability.However,in the same amount of polycarboxylic type superplasticizer,the kind and quantity of retarder could influence the compressive strength of 3 d,7d and 28d concrete.In this paper,the results could help to increase the level of compounding polycarboxylic type superplasticizer with other chemical admixtures and application in construction,and reduce the cost of composite admixture.