Analysis Of The Causes And Change Trend Of The Strength Of Concrete Body Structure In One Residential Area Of Guangzhou

The construction quality is always paid close attention by government and society. Thequality control of concrete and the evaluation of concrete strength are important content inconstruction quality control. The construction processing and even the safety of aconstruction structure are dependent on scientifically and objectively controlling the concretestrength in the concrete structure.Concrete is currently man-made building material used by largest amount in world. As akind of composite material, the concrete strengthen is affected by various factors. Thepurpose of this paper is to investigate the regularity of deviation among the strength ofconcrete body structure, the strength of the standard testing specimens and the designedstrength based on60000data about the strength concrete body structure and thecorresponding strength of the standard testing specimens collected by one quality supervisiondepartment in Guangzhou for6years. The candidate affecting factors were analyzed whichinclude the production process such as the selection of raw material, the mixture ratio designand the measurement of mixing process, the construction process such as the semi-finishedproduct transportation, the construction technology and the construction maintenance, and theconstruction quality control by related supervision management department.The analysis results show that the effective and accurate method are required anddecrease of the uncertain causing factors are decreased for beside enhancing of the inspectionof all processes such as the production, the construction and the experiment process. In ourcountry, evaluation of concrete strength is measured by strength of “standard curing testingspecimens” and “curing testing specimens under same condition”. Recently, the structureentity acceptance process was adopted to evaluate the quality of the concrete structure inaddition to evaluation of the standard curing testing specimens under same condition. Thestructure entity acceptance process can provide more actual quality condition of the concretestructure directly. The structure entity acceptance is surely better in allowable economical andtechnical condition. According to “Guangzhou City Construction Engineering QualitySupervision and Random Inspection Method of Solid Structure” enforced since April1st,2010, the new, expansion, alteration house construction engineering in the structural entity quality supervision and random inspection are required before the construction qualityacceptance of the foundation, the main structure section (sub-section). Results of samplinginspection are an important part of the project acceptance technology archives. Themandatory inspection of the concrete structure entity is necessary in quality acceptance ofconcrete structure.Although distinct difference between “standard curing testing specimens” and actualstructure piece in size, pouring, curing conditions (temperature, humidity, age), there aredifference between their body strengthens, and positive correlation between standard curingtesting specimens strength and actual structure body strength for same design strength. Thestandard curing testing specimen’s strength can reflect actual structure piece’s strength insome extent. There were some deviation between standard curing testing specimen’s strengthand actual structure body strength with designed strength, for the same duration and samedesigned strength level. The affecting factors were analyzed. Proposals and ideas for effectivecontrol of deviation were put forward.