Research On Cracking Cause And Control Strategy Of Concrete Used In Affordable Housing

The development of indemnificatory housing is an important measure to improve the living environment of ordinary people in our country.It has received strong support from the state and is an important part of housing construction during the 13 th Five-Year Plan period.Based on the investigation of the problems encountered in the construction and use of some public housing projects in China,this paper summarizes the quality problems faced by largescale public housing projects in China at present,studies the crack problems with great influence by using specific cases,and puts forward targeted prevention measures for the crack problems in key areas.The main contents of this these are as follows:(1)According to the actual investigation results,the quality problems frequently occurring in the affordable housing are elaborated in detail,the concrete cracking problems caused by different reasons are analyzed and summarized,and the general measures for preventing the concrete cracking of the affordable housing are proposed according to the engineering practices.(2)Based on a systematic summary of current concrete crack repair methods,the characteristics and repair steps of common crack repair methods such as filling,chemical grouting and self-repair are proposed,and the advantages,disadvantages and application scope of different repair methods are compared.The causes of cracks in different parts of the actual project and the corresponding repair measures and effects are analyzed according to some cracking concrete structures.(3)Aiming at the roof,toilet and other areas in the social security room where cracking has great influence and often contacts with water,the method of adding self-repairing materials is proposed to prevent and repair cracks.Concrete specimens with different amounts of permeable crystalline materials are designed and casted,and then they were predamaged under pressure load.After a certain period of immersion curing,crack repair and compressive strength repair are tested,and the optimal mix ratio is obtained according to the experiment results.(4)Aiming at mass concrete in the construction process of social housing,in order to avoid cracking caused by large temperature difference between inside and outside of concrete in the continuous casting process,six types of mix proportions are designed and expansive agents are added in some mix proportions to test the hydration heat.Then,the numerical model of actual engineering is established by using finite element software.According to different external environment and casting conditions,the temperature change during concrete casting is analyzed,the maximum temperature difference between inside and outside is obtained,the cracking situation during casting is predicted,and suggestions are put forward for the actual construction process.The actual pouring results verify the reliability of the numerical analysis.This these systematically summarizes the causes,manifestations and common repair methods of the crack of concrete,which can provide technical support and improve the construction quality of large-scale affordable housing construction.At the same time,the self-repair method of crack under water environment such as toilet and the mixture ratio and crack prediction method for mass concrete can provide reference for such key projects in the these housing.