發(fā)布時間：2018-04-17 03:17

  本文選題：凍融循環(huán) + 動態(tài)強度　； 參考：《寧波大學》2014年碩士論文

【摘要】：本文通過靜態(tài)壓縮和沖擊壓縮實驗研究凍融循環(huán)對陶�；炷羷討B(tài)力學性能的影響。利用WAW-2000微機控制萬能試驗機進行靜態(tài)壓縮實驗,試樣為尺寸150mm×150mm×150mm的砂漿混凝土和體積分數(shù)分別為15%、30%、40%的陶�；炷亮⒎襟w試樣及尺寸為Φ70 mm×35mm經(jīng)過不同凍融循環(huán)實驗的砂漿混凝土和體積分數(shù)分別為15%、30%、45%的陶粒混凝土。利用Φ74mm的分離式Hopkinson壓桿(SHPB)裝置進行沖擊壓縮實驗,試樣為尺寸Φ70 mm×35mm的四種陶粒體積分數(shù)經(jīng)過不同周次凍融循環(huán)的混凝土試樣,實驗打擊氣壓分別取0.3MPa、0.5MPa、0.7MPa。靜態(tài)實驗結(jié)果表明,陶�；炷恋撵o態(tài)抗壓強度和彈性模量隨著陶粒體積分數(shù)的增加而減小;當陶粒體積分數(shù)大于30%時,抗壓強度的減小程度明顯變小。與砂漿混凝土不同,陶�；炷脸叽缧�(yīng)并不明顯。動態(tài)SHPB實驗結(jié)果表明,陶�；炷恋膭討B(tài)抗壓強度隨著陶粒體積分數(shù)的增加而減小。在三個不同氣壓打擊下,砂漿混凝土的動態(tài)抗壓強度都明顯大于陶粒混凝土的動態(tài)抗壓強度;與砂漿混凝土有明顯差異的是陶�；炷恋膽�(yīng)力應(yīng)變曲線還存在平臺階段,即在應(yīng)力峰值之后,且應(yīng)變增加到一定值時,應(yīng)力隨應(yīng)變增加而減小的趨勢明顯變小,并會出現(xiàn)一定的波動現(xiàn)象,也就是說陶粒體積的增加,有效地提高了混凝土的沖擊韌性。隨著凍融循環(huán)周次的增加,砂漿混凝土和各組陶�；炷猎嚇拥膭屿o態(tài)抗壓強度及彈性模量都隨之減小。當凍融循環(huán)周次到40次后,砂漿混凝土和陶�；炷恋脑嚇颖砻婷撀鋰乐�,且隨著陶粒體積分數(shù)增加而趨于嚴重,此時陶粒混凝土的動態(tài)抗壓強度幾乎為未進行凍融循環(huán)的同類試樣的一半。而且當凍融循環(huán)溫度為-20℃~10℃時,砂漿混凝土和陶�；炷猎嚇拥目箟盒阅苊黠@低于經(jīng)過-10℃~10℃凍融循環(huán)的試樣。
[Abstract]:The effect of freeze-thaw cycle on dynamic mechanical properties of ceramsite concrete was studied by static compression and impact compression experiments.The static compression experiment is carried out by using WAW-2000 microcomputer controlled universal testing machine.The samples are mortar concrete of 150mm 脳 150mm 脳 150mm, cubic sample of 40% ceramsite concrete with volume fraction of 15%, mortar concrete of 桅 70 mm 脳 35mm with different freeze-thaw cycle test and ceramsite concrete with volume fraction of 15% and 30% respectively.The impact compression test was carried out with 桅 74mm split Hopkinson compression bar (SHPB) device. The samples were concrete samples with volume fraction of four kinds of ceramsite (桅 70mm 脳 35mm) subjected to different cycles of freeze-thaw cycles. The impact pressure of the test was taken at 0.3MPa (0.3MPa) and 0.5MPA (0.7MPa), respectively.The static experimental results show that the static compressive strength and elastic modulus of ceramsite concrete decrease with the increase of the volume fraction of ceramsite, and the decrease of compressive strength becomes smaller when the volume fraction of ceramsite is greater than 30%.Different from mortar concrete, the size effect of ceramsite concrete is not obvious.The dynamic SHPB experimental results show that the dynamic compressive strength of ceramsite concrete decreases with the increase of the volume fraction of ceramsite.Under three different air pressure, the dynamic compressive strength of mortar concrete is obviously higher than that of ceramsite concrete, and the stress-strain curve of ceramsite concrete still exists in platform stage.That is, after the peak stress, and when the strain increases to a certain value, the stress decreases obviously with the increase of strain, and there will be a certain fluctuation phenomenon, that is to say, the increase of the volume of ceramsite can effectively improve the impact toughness of concrete.With the increase of freeze-thaw cycle cycles, the static and static compressive strength and elastic modulus of mortar concrete and each group of ceramsite concrete samples decrease.After freezing and thawing cycles to 40 cycles, the surface of mortar concrete and ceramsite concrete become more and more serious with the increase of the volume fraction of ceramsite.At this time, the dynamic compressive strength of ceramsite concrete is almost half of that of similar specimens without freeze-thaw cycle.Moreover, when the freezing and thawing temperature is -20 鈩，

本文編號：1761826