Study On Synthesis And Property Of Anti-clay Polycarboxylate Superplasticizer

Polycarboxylic acid water reducer is a new generation of high performance water reducer,which has been widely used in major construction projects in recent years,because PCE has the advantages of high water reduction efficiency,strong structural design,and environmental protection without pollution.However,the research found that the polycarboxylic acid water reducer is greatly affected by the mud in the concrete.With the increase of the percentage of the mud,the performance of the PCE drops sharply,which seriously affects the flowability of the concrete because polycarboxylic acid water reducer is preferentially adsorbed on the soil when the system is mixed with mud,greatly reducing the content of water reducer that is originally used to disperse cement particles.Therefore,improving the resistance of polycarboxylic acid water reducer to soil has become an urgent problem in the industry.This project uses a free radical copolymerization method,with polyoxyethylene ether(HPEG)as the large monomer,acrylic acid(AA)as the small monomer,hydrogen peroxide and ascorbic acid(Vc)as the initiator,and mercaptoethanol(ME)as the chain transfer Agents,?-cyclodextrin,cationic DAC,and styrene are functional monomers,and polycarboxylic acid water reducing agents with good mud-resisting effect have been synthesized.Firstly,the effects of different synthetic methods and different ?-cyclodextrin feed ratios on the anti-mud effect of synthetic ?-cyclodextrin modified polycarboxylic acid water reducer were investigated.A large number of cement slurry fluidity experiments were conducted to test the effects of different proportions of montmorillonite on the anti-mud effect of the synthetic water reducing agent.Finally,a polycarboxylic acid superplasticizer PCE5 with good anti-mud effect was synthesized.Subsequently,the effects of different synthetic methods and cationic feed ratios on the anti-mud effect of the synthesized amphoteric polycarboxylic acid water reducer were explored.In order to improve the mud-resisting effect of the amphoteric polycarboxylic acid water reducing agent,styrene monomer was simultaneously introduced into the system,and the amphoteric polycarboxylic acid water reducing agent PCE7 with the best mud-resistant effect was finally synthesized.PCE5 and PCE7 were tested for actual application performance,and compared with ordinary polycarboxylic acid water reducer PCE0.The slump,expansion and compressive strength of C30 and C50 concrete with 5% mud content were measured.The results show that in C30 and C50 concrete with different mud content,the water reducing effect,dispersion retention ability and compressive strength of PCE5 and PCE7 are better than PCE0.It can be seen that the synthetic ?-cyclodextrin modified polycarboxylate Both acid water reducer and amphoteric polycarboxylic acid water reducer can improve the workability of concrete.Finally,the saturation content of PCE5 was 0.25%-0.30%,and the saturation content of PCE7 was 0.30%?0.35%.In this experiment,the cement slurry fluidity test was performedaccording to the amount of the water reducing agent being 0.13%(solid)of the total mass of cement and montmorillonite.Both of them did not reach the saturation levels of the two water reducing agents.A mud-resistant polycarboxylic acid water reducing agent has mud-resistant effect.