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(1 上海市建筑科學(xué)研究院有限公司, 上海 200032;2 上海市工程結(jié)構(gòu)安全重點(diǎn)實(shí)驗(yàn)室, 上海 200032)

摘要: 現(xiàn)場(chǎng)檢測(cè)混凝土強(qiáng)度的推定值同時(shí)受到樣本強(qiáng)度平均值和標(biāo)準(zhǔn)差的影響,而不同測(cè)試方式下樣本強(qiáng)度標(biāo)準(zhǔn)差的差異很大. 對(duì)立方體、圓柱體兩種同條件養(yǎng)護(hù)試塊和回彈法、鉆芯法兩種方法檢測(cè)混凝土強(qiáng)度的平均值和標(biāo)準(zhǔn)差進(jìn)行對(duì)比試驗(yàn),同時(shí)研究了芯樣直徑、高徑比、粗骨料表面積占比等因素對(duì)芯樣強(qiáng)度平均值和標(biāo)準(zhǔn)差的影響. 試驗(yàn)結(jié)果表明,與同條件養(yǎng)護(hù)立方體試塊相比,芯樣強(qiáng)度的平均值偏大,標(biāo)準(zhǔn)差略偏大;回彈強(qiáng)度的平均值偏小,標(biāo)準(zhǔn)差明顯偏小;?150、?105、?75 三種芯樣中,相對(duì)于 ?105 芯樣,?150 芯樣的強(qiáng)度平均值偏小,而 ?75 芯樣的強(qiáng)度標(biāo)準(zhǔn)差偏大;小高徑比芯樣與標(biāo)準(zhǔn)芯樣的強(qiáng)度平均值之間有較明確的換算關(guān)系,而前者的強(qiáng)度標(biāo)準(zhǔn)差略小于后者,故小高徑比芯樣仍有較大的利用價(jià)值;芯樣強(qiáng)度標(biāo)準(zhǔn)差表現(xiàn)出隨外露粗骨料尤其是大粒徑粗骨料表面積占比增大而增大的趨勢(shì),這可以解釋芯樣強(qiáng)度標(biāo)準(zhǔn)差相對(duì)于立方體試塊強(qiáng)度標(biāo)準(zhǔn)差偏大的原因.

關(guān)鍵詞: 混凝土抗壓強(qiáng)度; 回彈法; 鉆芯法; 芯樣直徑; 高徑比; 粗骨料表面積占比

中圖分類(lèi)號(hào):TU528. 1 文獻(xiàn)標(biāo)志碼:A 文章編號(hào):1002?848X(2022)08?0105?07

DOI:10. 19701 / j.jzjg.LS202101

Comparative experimental research on concrete compression strength under different testing methods

ZHENG Shiju1,2, LIU Hui1,2, JIANG Lixue1,2

(1 Shanghai Research Institute of Building Sciences Co., Ltd., Shanghai 200032, China; 2 Shanghai Key Laboratoryof Engineering Structure Safety, Shanghai 200032, China)

Abstract: The presumed value of concrete strength tested on site is affected by both the mean value and standard deviationof the sample strength, and the standard deviation of the sample strength varies greatly under different testing methods. Themean value and standard deviation of the concrete strength of the cube and cylinder test blocks under the same conditions ofcuring as well as the rebound method and the core drilling method were compared. The influence of core sample diameter,height?diameter ratio and surface area ratio of coarse aggregate on the mean value and standard deviation of the samplestrength of testing samples was also studied. The test results show that, compared with cube test block under the sameconditions of curing, the mean value of core sample strength is larger and the standard deviation is slightly larger. The meanvalue of the rebound strength is smaller and the standard deviation is obviously smaller. Among ?150、?105 and ?75 coresamples, when compared with the ?105 core sample, the mean strength of the ?150 core sample is smaller and the strengthstandard deviation of the ?75 core sample is larger. There is a clear conversion relationship between the mean strengths ofthe core samples with small height?diameter ratio and standard core samples, and the strength standard deviation of theformer is slightly smaller than that of the latter, so the core sample with small height?diameter ratio still has a considerableapplication value. The standard deviation of core sample strength shows a growth trend with the increase of the surface arearatio of exposed coarse aggregate, especially large particle size coarse aggregate, which can explain the reason why thestandard deviation of the core sample strength is larger than that of the cube test block.

Keywords:concrete compression strength; rebound method; core drilling method; core sample diameter; height?diameterratio; surface area ratio of coarse aggregate

∗國(guó)家重點(diǎn)研發(fā)計(jì)劃項(xiàng)目(2017YFC0806100),上海市科學(xué)技術(shù)委員會(huì)項(xiàng)目(19DZ1202400).

第一作者:鄭士舉,碩士,高級(jí)工程師,一級(jí)注冊(cè)結(jié)構(gòu)工程師,主要從事既有建筑鑒定與加固研究,Email:zsj85408048@ 163.com.

[引用本文] 鄭士舉,劉輝,蔣利學(xué). 不同測(cè)試方式下混凝土抗壓強(qiáng)度對(duì)比試驗(yàn)研究[ J]. 建筑結(jié)構(gòu),2022,52(8):105?111. ZHENG Shiju, LIU Hui, JIANG Lixue. Comparative experimental research on concrete compression strengthunder different testing methods[J]. Building Structure,2022,52(8):105?111.