Effect Of Co-poly Carboxylic Acid Water Reducing Agent On Hydration Process And Dispersion Of Cement

Development of co-poly carboxylic acid Water reducing Agent (WRA) was a modern frontier research project. The co-poly carboxylic acid WRA was characteristic of row additive, higher fluidif ication effect, and preventing concrete mix from slump-loss with time duration. The domestic research of co-poly carboxylic acid WRA was at first step now.In this paper, a class of co-poly carboxylic acid Water reducing Agent was designed from the connection of chemical classification with the structure of poly -carboxyl series WRA. The comb-like copolymer structure of co-poly carboxylic acid Water reducing Agent was "carboxylic group-ether link-ester link". In chapter 3, the synthetic method of co-poly carboxylic acid WRA and the effect of the molar of every reaction monomer on dispersing property were studied. The orthogonal experimental results showed that, when the molar of reaction monomer was consisted of acrylic acid(0.05mol), maleic anhydride (0.04mol) .acrylamide (0.10mol), HPA(0.15) , PEA(0.05), polypropyl sodium sulfonate(0mol), the carboxylic acid copolymer had best behavior. In chapter 4, the influence of co-poly carboxylic acid Water reducing Agent on hydration process and the hydration products of cement. By use of ESEM the micro-morphology of the hardened cement paste added with the carboxylic acid copolymer .The results showed that the carboxylic acid copolymer improve the dispersion and thedispersing stability of cement, can retard hydration process of cement efficiently in early ages, make the hydrations of clinker with gypsum better than that didn't add with carboxylic acid copolymer. In chapter 5, the effect of side-chains of Co-poly carboxylic acid upon the dispersion, the hydration and the microstrures of hardended pastes of composite binder were studied. The studied results showed that a type of carboxylic acid with better dispersion can be synthesized by the way of change of the ratio of the different side-chains. Experimental tests showed that: when the molecular of the polyethylene glycol of 400:600 = 1:1 (molar ratio), the synthesis of the co-poly carboxylic acid had an excellent dispersion effect, it had good fluidity and dispersing property of cement past. The effect of side-chains of co-poly carboxylic acid upon the hydration process and the hydration products of cement the same as the influence on the dispersion. The more dispersion of co-poly carboxylic acid had the bigger effect of retarding hydration degree of cement and hydration process of cement efficiently in early ages.