Preparation And Application Of Compound Concrete Curing Agent

Reasonable and sufficient curing is an effective means to improve the durability ofconcrete. As a new method curing agents attract more and more attention due to its lots ofadvantages of efficiency, convenience and adaptability etc. The curing agents which are beingdeveloped at present in the country have the disvantages of single mechanism and lowwater-retention rate, and research on the performance of the curing agents is only limited tothe mechanical property and durability of the concrete, while there is less study on estimationof curing effect and microcosmic mechanism of curing agents.Therefore, there are greatsignificance to prepare a compound curing agent and study its performances.Based on the curing mechanism of various materials, this paper use the orthogonalexperiment to analysis how the organic film-forming component, inorganic densifingcomponent and enhancing component impact on the strength and water-retention rate of thecement mortar, then to give the best proportion of curing agent.Moreover, this paper analyzedthe concrete’s water retention performance, mechanical performance,the bonding performanceand durable performance compared to various curing methods and kinds of curing agent.Atthe same time, the method of surface water absorption and curing efficiency index methodwhich is based on springback intensity were used to evaluate the curing effect of compoundcuring agent.At last, XRD and SEM microscopic analysis method were applied to study themechanism of the curing agent.The results show that:(1)The performance of compound curing agent were better byadding pure acrylic emulsion, sodium metasilicate, triethanolamine and methyl siliconealcohol sodium on the basis of paraffin emulsion, the good organic/organic andinorganic/organic composite system were formed to give full play to synergistic effect,3deffective water-retaining rate were nearly80%,28d compressive strength ratio reached95.5%.(2)The compressive and flexural strength of concrete cured by the curing agent were higherthan the control sample cured in dry curing condition during the curing age, closed to thestandard curing and higher than that of water curing.(3)The water-retention ability ofcompound curing agent were better than the simple curing agent, the performance varied indifferent types of curing agent, the spraying dosage of curing agent should be controlled in250~300g/m2.(4)The compound curing agent overcomed the weaknesses on bondingperformance of after-pouring concrete, splitting tensile strength was only low0.27MPa thanone-time molding standard curing specimen.(5)Compound curing agent could reduce thedrying shrinkage of concrete specimens effectively, and improved the permeability of concrete, crack resistance and wear resistance, the7d drying shrinkage of concrete value wasreduced by41.1%,28d porous height ratio is85.9%, had lower3d crack number and areathan the control sample, the rate of crack reduce was0.987.abration of concret was1.96kg/m2when spraying dosage was300g/m2.(6) The method of surface water absorption and curingefficiency index (CEI) method could evaluate the curing effect successfully,3d surfacewater-absorption rate of concrete cured by curing agent was3.4×10-6cm2/s, it was reduced by39.2%than the control sample,CEI of concrete cured by curing agent was higher than controlsample cured in dry condition.(7)The result of XRD and SEM showed that the curing agentcould accelerate the hydration process of cement to produce more hydration products, crystalgrained a large size, and overlap each other to form compact structure.