Study On Synthesis And Performance Of Low Air Entrained Poly-carboxylic Superplasticizer PCS-1

The polycarboxylic of water-reducing agent was characteristic of high water-reducing ratio and preventing concrete mix from slump loss with duration of time. Nowadays, poly-carboxylic acid water-reducer agent has been widely studyed. In this dissertation, Polycarboxylic water-reducers (Low air-entraining type poly-carboxylic superplasticizers, abbreviated as PCS-1) was synthesized which had macromonomers with low air-entraining function, meanwhile PCS-1 had been developed and tested for properties.According to the "purpose building" approach, and the relation between chemical structure of the Polycarboxylic of superplasticizers and its properties were discussed. Acrylic acid and isobutyl acrylate and polyoxyethylene (PMA) and methoxypoly (Multiblock EO/PO Polyether) acrylic (MPEO/POAA), which have the properties of high water-reducing and highly slump retaining ability and low air-entraining, were added to the polymer through esterify and polymerization. Intermediate macromonomers (MPEO/POAA) and PCS-1 were synthesized by way of orthogonal testing. The technical parameters were optimized through experiments. At last through the studying of surface properties such as FTIR ,UV-Vis spectrophotometer, surface tension, Zeta potential, inherent viscosity, esterification productivity and so on, discussed the water reducing mechanism. Research showed that the linchpin is to make different groups reasonably chained with the key group.PCS-1 was developed with the optimal polymerizing technology, and the properties of cement paste and mortor and concrete with PCS-1 were tested. Comparing with other kinds of high performance water-reducing agent, the concrete experimental results showed that PCS-1 has the advantages of excellent fluidity of cement, high water- reducing ratio, good slump-loss resistant property and strength enhancement. PCS-1 overcame the concrete's low strength because of high air-entraining. When water-cement ratio of W/C=1.0:0.3, W (PCS-1) =0.5%, the fluidity of cement grout reached 32.8cm, while air-content of concrete only was 2.8%, water-reducing ratio was33.2%, slump conservation rate was 92%~97% during one hour, and 28 d compressive strength ratio of concrete adding PCS-1 was 167%. PCS-1 was a kind of poly-carboxylic acid superplasticizers with low air-entraining function.