Experimental Study On Effect Of Internal Curing On Performance Of Self-Compacting Concrete

Due to its outstanding working performance and high productivity,self-compacting concrete(SCC)is frequently used in water conservation,bridge,and tunneling projects,particularly for the building of large volume structures and high density reinforced concrete structures with distinctive benefits.However,the conventional curing method is barely effective due to the abundance of SCC cementitious material and the high density,which puts the structure at risk for shrinkage and cracking at an early stage.Self-compacting concrete can successfully reduce structural shrinkage cracking through the use of in-concrete curing technology,which is valuable for promotion and has a broad range of potential applications.The following studies were conducted to investigate the effect of internal curing on the performance of SCC and to demonstrate the vital elements of the mix design for internal curing self-compacting concrete:Orthogonal experimental design was adopted to determine the mix of SCC test.Explore the influence rule of ceramide content and prewetting time on the performance of self-compacting concrete cured in ceramide lightweight aggregate(CIC-SCC),and determine the optimal ceramide content range and prewetting time with comprehensive performance of CIC-SCC.The optimal particle size range of SAP was determined through comparative tests,and the influence law of the content of highly absorbent resin(SAP)and additional water diversion on the performance of self-compacting concrete cured in highly absorbent resin(SIC-SCC)in SAP was explored,and the optimal SAP content range and additional water diversion conditions of SIC-SCC with comprehensive performance were defined.Self-compacting concrete’s shrinkage prediction algorithm for interior curing was developed.The points that follow are the study’s substantial conclusions:(1)Establish the SCC’s design blend ratio.Among them,the percentage of sand is 50%,the percentage of fly ash is 25%,the percentage of mineral powder is 10%,and the percentage of water reducing substance is 1.2%.(2)With the increasing amount of ceramic pellets,the working performance and frost resistance of CIC-SCC were gradually improved;The compressive strength decreased gradually at day 7 and day 28,and increased first and then decreased at day 60.Auto-shrinkage and drying shrinkage decrease gradually.Insufficient pre-wetting time of ceramide will result in poor working performance of CIC-SCC and aggravate the development of early self-shrinkage.Prolonging the prewetting time of ceramides can effectively alleviate the decline in the early strength of CIC-SCC,and is beneficial to the development of the later strength.The optimum dosage range of ceramide is 16%～20%.The optimum prewetting time is 12h～24h.(3)The shrinkage value of SIC-SCC declines with an increase in SAP admixture when no additional water is added,but the effect is undesirable;the mixture is not liquid enough,and working performance incrementally decreases.The self-shrinkage and drying shrinkage of SIC-SCC gradually decreased after the additional introduction of the appropriate the amount of internal maintenance water,and the work performance and frost resistance significantly improved.The development of the early strength of SIC-SCC remains steady and the hydration of SIC-SCC gets better,which is beneficial for the development of the later strength.Yet,after increasing SAP dosing,the early strength of SIC-SCC gradually decreases and the later strength increases and then decreases.When anything is taken into account,the best SAP particle size goes among 80 to 120 m,the best admixture falls among 0.2%to 0.3%,and the additional water introduction goes among 10 kg/m~3 to 20 kg/m~3.(4)The development of the shrinkage value of internally curing self-compacting concrete can be accurately anticipated owing to the establishment of the shrinkage prediction model.