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(清華大學(xué)土木工程系, 北京 100084)

摘要: 通過試驗(yàn)探討了初始預(yù)壓應(yīng)力水平對(duì)混凝土超低溫下預(yù)壓性能的影響,考察的應(yīng)力水平為 0. 2、0. 4 及0. 6,選取的作用溫度分別為-40、-80、-120℃ 及-160℃ . 結(jié)果表明,不同初始預(yù)壓應(yīng)力水平混凝土的預(yù)壓應(yīng)力損失量在各降溫區(qū)間的降溫階段隨降溫基本上呈線性增大趨勢(shì),而其恒溫階段隨恒溫時(shí)間則先有所增大后呈減小甚至出現(xiàn)預(yù)壓應(yīng)力損失量恢復(fù)狀,且作用的低溫越低時(shí)恢復(fù)越明顯;混凝土預(yù)壓應(yīng)力損失率在各降溫區(qū)間的降溫階段隨初始預(yù)壓應(yīng)力水平提高而降低,但恒溫階段則變得較為復(fù)雜;不同初始預(yù)壓應(yīng)力水平混凝土預(yù)壓應(yīng)力損失量均隨降溫點(diǎn)溫度的降低呈現(xiàn)出近于線性增大的趨勢(shì),而隨溫均點(diǎn)溫度的降低則呈先逐漸增大之后趨于平緩的變化態(tài)勢(shì). 結(jié)合試驗(yàn)數(shù)據(jù),給出了降溫點(diǎn)和溫均點(diǎn)時(shí)混凝土預(yù)壓應(yīng)力損失量隨溫度變化的擬合關(guān)系式.

關(guān)鍵詞: 預(yù)應(yīng)力混凝土; 超低溫; 預(yù)壓性能; 預(yù)壓應(yīng)力損失

中圖分類號(hào):TU528. 1 文獻(xiàn)標(biāo)志碼:A 文章編號(hào):1002-848X(2023)05-0041-06

DOI:10. 19701 / j. jzjg. 20201622

Experimental study on influence of initial preloading stress levels on preloading performance of concrete exposed to ultralow temperature

SHI Xudong, HAN Daquan, LI Yaqiang

(Department of Civil Engineering, Tsinghua University, Beijing 100084, China)

Abstract: The effect of initial preloading stress levels ( IPSLs) on the preloading performance of concrete exposed toultralow temperature was discussed through experiment. The examining initial preloading stress levels acting on specimenconcrete are 0. 2, 0. 4 and 0. 6, and the corresponding temperatures including - 40, - 80, - 120℃ and - 160℃ arerespectively exerted. The test results show that the preloading stress loss of concrete with different IPSLs increases linearlywith the decrease in temperature during the cooling stage of each ultralow temperature range. However, the preloadingstress loss of concrete increases first and then decreases or even recovers with increase in the time during the constanttemperature stage, and the lower the exerted lower limit temperature, the more obvious the recovery. The preloading stressloss rate of concrete decreases with the increase in the IPSL during the cooling stage of each ultralow temperature range, butit will become complicated during the constant temperature stage. The preloading stress loss of concrete with different IPSLsshows a nearly linear increase trend with the decrease in temperature at the cooling target point. But it will have a differentchanging trend which increases first and then flattens at the temperature uniformity target point. According to the test data,the preloading stress loss of concrete with temperature at the cooling target point and the temperature uniformity target pointwas given.

Keywords:prestressed concrete; ultralow temperature; preloading performance; preloading stress loss

∗國(guó)家自然科學(xué)基金項(xiàng)目(51878375).

第一作者:時(shí)旭東,博士,教授,主要從事超低溫混凝土性能研究,Email: shixd@ mail. tsinghua. edu. cn.

[引用本文] 時(shí)旭東,韓大全,李亞強(qiáng). 初始預(yù)壓應(yīng)力水平對(duì)混凝土超低溫下預(yù)壓性能影響試驗(yàn)研究[ J]. 建筑結(jié)構(gòu),2023,53( 5):41-46. SHI Xudong,HAN Daquan,LI Yaqiang. Experimental study on influence of initial preloadingstress levels on preloading performance of concrete exposed to ultralow temperature[J]. Building Structure,2023,53(5):41-46.