Study On The Synthesis And Perpormance Of Polycarboxylated Superplasticizers

With the development of infrastructures, the rapid increase in demand of concrete. Concrete is the largest amount of artificial materials in the world of today. In 2014, cement production of C hina was 2.48 billion tons, accounted for more than 80 % of world cement production. these cements can be configured with 8 billion cubic meters of concrete. Superplasticizer is one of the main types of concrete admixtures, as important ingredient of high-performance concrete, it attracted extensive attention.Water reducer destroy beginning period cement granular flocculation structure,through electrostatic repulsion force and steric size of polymers, release free water, The paste flow increases. It can reduce concrete mixing water,While ensuring the concrete rheological properties. The dispersion of water reduce for cement, promote hydration of cement, improve the range of technicalimprove the range of technicalAs the third generation superplasticizer, polycarboxylic superplasticizer not only have high performance about water-reducing rate,but agent not only rate is high, and has a low dosage, slump retention capacity of fresh concrete is high, and hardened concrete smaller shrinkage, low content of alkali, chlorine- free and environmentally friendly and so on, and suitable for high-performance concrete.It has a professional welcome, represents a concrete water reducing agent development direction in the future. Last more than 10 years, the rapid development of domesticte chnology of polycarboxylic superplasticizer,but still in the primary stage of the ascendant. Polycarboxylic type high performance water-reducing agent: preparation, properties and applications, and many other aspects of the subject are required to study, research and exploration. The topic of this paper focuses on research and development of polycarboxylate superplasticizer.In the paper, using acrylic ac id(AA), sodium methallyl sulfonate(MAS) as the main chain, methyl polyoxyethylene ethers(TPEG) as the side chain. in orthogonal test and analysis of a single factor, the best synthetic condition is determined:(1)n(TPEG):n(AA):n(HGA):n(H2O2):n(VC)=1:4.20:0.13:0.03:0.23, the reaction temperature is at 30 ℃, the reaction time is 4 h. The neutralizing sample has high water reducing rate. Concerning solid dosage 0.2 %, the paste flow can attain 307 mm, water reducing rate was 49.14 %, the strength ratio outstripped 210 %.(2)n(TPEG):n(AA):n(MAS):n(APS)=1:2.0:0.06:0.20,the reaction temperature is at 60 ℃, the reaction time is 4 h.The neutralizing sample has good slump stability. Concerning solid dosage 0.2 %, the cement paste initial and 1h of fluidity is 294 mm and 296 mm, water reducing rate was 35.02 %, the strength ratio of every age outstripped 220 %. The analysis of ether-type polycarboxylate superplasticizer by IR, showed effective group. and the relevant information about molecular weight of simply by GPC, Adsorption capacity, images studies, the water reducing mechanism was further exploited.