【作者】 李久明；

【导师】 桂国庆； 黄素平；

【作者基本信息】 南昌大学 ， 结构工程， 2011， 硕士

【摘要】 预拌混凝土的推广应用是一项全新的绿色事业和系统工程,回弹法是混凝土结构现场强度检测应用最为广泛的无损检测技术方法。本文针对吉安地区预拌混凝土建立回弹测强曲线,研究了不同材料组成、施工及成型工艺的差异因素对回弹测强精度的影响,同时考虑试块强度与结构实体强度的差异进行了取芯试验修正及工程验证。得出以下结论：(1)通过对本地区混凝土试块回弹测强数据混合回归及误差比较分析,指出混合回归曲线对不同材料组成及成型工艺混凝土测强精度存在较大差异,提出建立本地区测强曲线,应以相对误差最小为目标及考虑卵石、碎石、泵送、非泵送不同情况,以提高回弹曲线测强精度的措施。(2)考虑卵石、碎石、泵送与非泵送不同情况对试块回弹测强数据分类回归及误差比较分析指出：本地区卵石非泵送和卵石泵送混凝土按试块试验回归曲线与国家《回弹法检测混凝土抗压强度技术规程(JGJ/T 23—2001)》(以下简称《规程》)统一曲线推定的强度相对误差基本一致；碎石非泵送混凝土和碎石泵送混凝土按试块试验回归曲线与国家统一曲线推定的强度相对误差差异较大,试块试验回归曲线测强精度明显优于《规程》统一曲线。(3)考虑试块强度与结构实体强度的差异,本文对试块试验建立的回弹测强曲线进行了取芯验证和修正,结论提出：1)国家《规程》统一曲线测强分别采用修正系数值1.034和1.065,适用于本地区C20-C40卵石非泵送混凝土和C20-C40卵石泵送混凝土回弹测强。2)本地区碎石非泵送混凝土修正后测强曲线(f=0.05371×R1.8682×10-0.03980d)适用于本地区C20-C60碎石非泵送混凝土回弹测强；碎石泵送混凝土修正后测强曲线(,=030588×R141204×10-003163d)适用于本地区C20-C60碎石泵送混凝土回弹测强。本课题研究结果可作为研制江西省(吉安)地区预拌混凝土测强曲线及全国统一测强曲线的重要依据。更多还原

【Abstract】 The spread and application of ready-mixed concrete is a new green enterprise and system engineering. Rebound method is the most widely used nondestructive examination method in application of field strength test on concrete construction. In view of strength curve for rebound method built by ready-mixed concrete in Ji’an, this paper studies the effects of differentiating factor on accuracy of rebound test caused by different materials, different constructions and molding process, and has the modification of coring experiment and the engineering test considering the differences caused by the strength of test block and construction entity. The following conclusions:(1) By analysis of mixed regression and error comparing on the rebound test data of concrete test block at local area, this paper points out that major differences in the strength test accuracy of molding process and different material compositions are caused by the mixed regression curve, proposes to set up the strength test curve at local area, and puts forward the measures to improve the accuracy of strength test curve aiming at minimizing relative error, with consideration of different situations caused by pebbles, rubbles, pumping or non-pumping.(2) Considering different situations caused by pebbles, rubbles, pumping or non-pumping influencing classified regression and error comparing on the rebound test data of concrete test block, this paper points out that there exists minor relative errors between the regression curve of test block examination in the pumping and non-pumping of pebbles in local area and the strength of homological curve prescribed by "Technical Specification for Inspection of Concrete Compressive Strength by Rebound Method" (JGJ/T23-2001) in our country; major relative errors exists between the regression curve of test block examination in the pumping and non-pumping of rubbles in local area and the strength of homological curve in our country; and the strength test accuracy of regression curve on test block examination is significantly superior than homological curve prescribed by " Technical Specification for Inspection of Concrete Compressive Strength by Rebound Method " (JGJ/T23-2001)(3) Considering the differences of the strength of test blocks and construction entities, this paper has the modification of coring experiment and the engineering test on the curve of rebound strength test set by test block examination, and gets such conclusions:1)The strength of homological curve prescribed by《Technical Specification for inspection of Concrete Compressive Strength by Rebound Method》in our country adopts modified coefficient K value 1.034 and1.065 respectively, which applies to the test strength of the C20-C60 pumping and non-pumping rubble concrete in the local area.2) The post-modified strength curve of non-pumping rubble concrete in the local area (ft4= 0.05371×R1.8682×10-0.03980d) applies to the rebound strength of the C20-C60 non-pumping rubble concrete in the local area. And the post-modified strength curve of pumping rubble concrete (ft5= 0.30588×R1.41204×10-0.03163d) applies to the rebound strength of the C20-C60 pumping rubble concrete in the local area.The results of this study can be the important basis on researching the strength curve of ready-mixed concrete in Ji’an of Jiangxi province and homological strength curve in the country.更多还原