酸雨環(huán)境下老舊磚砌體的抗壓性能

王鳳池　趙晗宇　劉昊宇　任紹南

摘要：

為研究酸雨環(huán)境下老舊砌體抗壓力學(xué)性能退化規(guī)律，實(shí)驗(yàn)室配置了PH值分別為1.5、25和3.5的3種硫酸和硝酸混合溶液來(lái)模擬酸雨環(huán)境，采用完全浸泡加速腐蝕的試驗(yàn)方法對(duì)磚、砂漿和磚柱進(jìn)行不同程度的腐蝕，并測(cè)定其抗壓強(qiáng)度。試驗(yàn)表明，隨著腐蝕時(shí)間的增加，砂漿試塊抗壓強(qiáng)度先增大后降低；磚試塊抗壓強(qiáng)度隨腐蝕時(shí)間的增加而降低；模擬酸雨溶液PH值越小，砂漿和磚試塊抗壓強(qiáng)度降低程度也愈大；磚柱極限承載力和彈性模量均隨腐蝕時(shí)間的增加而降低，且模擬酸雨溶液PH值越小，降低程度愈大；隨著腐蝕時(shí)間的增加，磚柱初始剛度逐漸減小，極限破壞位移增大；模擬酸雨溶液PH值越小，磚柱在達(dá)到峰值荷載時(shí)的變形值越小，脆性愈大；基于試驗(yàn)結(jié)果，建立了酸雨環(huán)境下磚柱應(yīng)力應(yīng)變曲線上升段統(tǒng)一數(shù)學(xué)表達(dá)式及酸雨侵蝕后普通燒結(jié)粘土磚砌體剩余抗壓強(qiáng)度回歸公式。

關(guān)鍵詞：

酸雨；砂漿；磚柱；腐蝕；抗壓強(qiáng)度；應(yīng)力應(yīng)變曲線

中圖分類(lèi)號(hào)：TU362

文獻(xiàn)標(biāo)志碼：A文章編號(hào)：16744764（2017）02014008

Abstract：

Three kinds of mixed solutions of sulfuric acid and nitric acid with the pH value of 1.5， 2.5 and 3.5 were prepared in the laboratory to simulate acid rain environment. The compression properties of brick masonry exposed to acid rain environment was studied. The brick samples， mortar samples and brickcolumns were completely immersed in the simulated acid solutions. After being exposed to the solutions for a certain period， compression tests were performed on the three types of the samples. The results showed that with the increase of corrosion time the compressive strength of mortar samples increased firstly and then decreased， whilst the brick samples always decreased. And the lower the pH value of the solutions was， the more the compressive strength of mortar samples and brick samples decreased. With the increase of corrosion time， the ultimate bearing capacity and elastic modulus of brickcolumns showed a trend of decrease， and the lower the pH value of the solutions was， the more obvious the trend was. With the increase of corrosion time， the initial stiffness of brickcolumns decreased， ultimate failure displacement increased. With the pH value of the solutions declining， the deformation of brickcolumns under ultimate load decreased but the brittleness increased. Based on the experimental results， regression formulas were put forward to describe the ascending part of the stressstrain curve and the remaining compressive strength of brickcolumns exposed to acid rain environment.

Keywords：

acid rain； mortar； brickcolumn； corrosion； compressive strength；stressstrain curve

酸雨已成為世界性環(huán)境問(wèn)題，中國(guó)酸雨已覆蓋國(guó)土面積的40%，成為繼歐洲、北美之后第三大酸雨區(qū)[12]。酸雨中含有H2SO4：HNO3等酸性物質(zhì)，可以使服役于酸雨區(qū)的磚砌體結(jié)構(gòu)受到不同程度的腐蝕，加速結(jié)構(gòu)老化進(jìn)程，不但降低結(jié)構(gòu)的安全性，而且給國(guó)民經(jīng)濟(jì)帶來(lái)巨大損失。

學(xué)者們相繼開(kāi)展了酸雨對(duì)混凝土性能影響方面的研究工作，研究大多采用加速腐蝕的試驗(yàn)方法，在對(duì)不同腐蝕程度的混凝土、抗壓強(qiáng)度、抗拉強(qiáng)度和質(zhì)量變化[38]以及不同類(lèi)型水泥的抗酸雨侵蝕性能等方面[911]取得不少成果，得到了初步定性的結(jié)論。……