Study On The Mechanics And Durability Of Self-compacting Concrete Cured In Red Brick Sand

Self-compacting concrete has the unparalleled advantage of ordinary concrete,that is,it can be leveled automatically without vibration,which has made it a lot of research and practical engineering applications in recent years.However,compared with ordinary concrete,self-compact concrete has a large amount of mineral admixtures and high-efficiency water-reducing agents,so the internal humidity decreases rapidly in the early stage,which will cause a higher shrinkage value and cause cracking.After research,internal conservation can effectively solve this problem.If ordinary concrete is cured inside red brick sand,after vibration,it may cause the concrete to segregate or the red brick sand to float,but this problem will not occur when red brick sand is used as an internal curing material in self-compacting concrete.As a kind of construction waste,bricks have a wide range of sources and low cost.This way of recycling waste is in line with the concept of green building.The experimental content of this paper mainly includes the study of the properties of red brick sand and the effect of red brick sand partially replacing river sand on the performance of self-compacting concrete.This paper adopts red brick sand with different particle sizes and uses red brick under different replacement ratios.Sand is used for internal curing of self-compacting concrete.The main research results are as follows:1.The basic physical indicators such as the apparent density of red brick sand are studied,and the water absorption and release laws of red brick sand are studied and analyzed.It is confirmed that red brick sand can be used as an internal curing material.The saturated red brick sand has been studied to replace river sand.The effect on the yield stress and plastic viscosity of self-compacting mortar,the results show that the rough surface of red brick sand will cause the mortar yield stress and plastic viscosity to show an upward trend.At the same time,the replacement of saturated red brick sand will reduce the Slump spread.2.The effect of red brick sand on the shrinkage and compressive strength of self-compacting concrete was studied.As the proportion of red brick sand replacing river sand increased,the self-compacting and drying shrinkage of self-compacting concrete showed a downward trend.It has little effect on the strength of self-compacting concrete during the first 7 days,and its strength decreases with the increase of the replacement amount of red brick sand.The later-stage strength of small-grained red brick sand self-compacting concrete is greater than the strength of large-grained self-compacting concrete with the same replacement ratio..3.The effect of red brick sand on the durability of self-compacting concrete is studied.For the carbonization resistance,the 56 d carbonization depth has a positive correlation with the replacement ratio of red brick sand.Moreover,the carbonization depth has little relationship with the particle size of red brick sand,and the replacement ratio is the same.The particle size of red brick sand is basically the same.For the resistance to chloride ion penetration,the chloride ion permeability coefficient is positively related to the replacement ratio of red brick sand.And the replacement of small particle red brick sand has a slightly smaller impact on the chloride ion permeability coefficient.At the same replacement ratio,the chloride ion permeability coefficient of small-sized red brick sand is slightly lower.The above conclusions verify that red brick sand as an internal curing material for self-compacting concrete is feasible under a limited replacement ratio,and its impact on the performance of self-compacting concrete is limited.