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（1 內(nèi)蒙古科技大學(xué)土木工程學(xué)院， 包頭 014010； 2 萊蕪城市發(fā)展集團(tuán)有限公司， 萊蕪 271100）

［摘要］通過(guò)在含有100%再生粗骨料的混凝土中同時(shí)摻入20%的礦渣和0%，15%，30%摻量的粉煤灰，并進(jìn)行碳化、凍融和凍融碳化耦合試驗(yàn)，研究?jī)鋈诤吞蓟h(huán)境對(duì)再生混凝土耐久性的影響，對(duì)比分析試件抗壓強(qiáng)度、質(zhì)量損失率、相對(duì)動(dòng)彈性模量、碳化深度的變化規(guī)律，建立凍融-碳化耦合作用下礦渣-粉煤灰再生混凝土抗壓強(qiáng)度模型。結(jié)果表明：粉煤灰摻量為15%時(shí)，再生混凝土的抗凍性能最好，當(dāng)凍融次數(shù)大于100次后，粉煤灰對(duì)再生混凝土抗凍性能的促進(jìn)作用開(kāi)始減弱；粉煤灰摻量越多，再生混凝土的抗碳化性能越弱，當(dāng)粉煤灰摻量為30%時(shí)，其碳化深度是粉煤灰摻量為0試件的2倍以上；在凍融-碳化耦合環(huán)境中，凍融作用促進(jìn)了碳化深度的增長(zhǎng)，碳化作用加劇了礦渣-粉煤灰再生混凝土的凍融破壞；建立的礦渣-粉煤灰再生混凝土凍融-碳化耦合抗壓強(qiáng)度模型能較好地反應(yīng)凍融-碳化耦合環(huán)境下的抗壓強(qiáng)度退化規(guī)律。

［關(guān)鍵詞］凍融循環(huán)； 碳化； 粉煤灰摻量； 再生粗骨料； 凍融-碳化耦合作用； 耐久性； 抗壓強(qiáng)度模型

中圖分類號(hào)：TU528文獻(xiàn)標(biāo)識(shí)碼：A文章編號(hào)：1002-848X(2020)15-0085-06

Experimental study on slag-fly ash recycled concrete under the action of  freeze-thaw-carbonation coupling

WANG Chenxia1, LIU Jun1, CAO Fubo1, WANG Zhe2

(1 School of Civil Engineering, Inner Mongolia University of Science and Technology, Baotou 014010, China;2 Laiwu City Development Group Co., Ltd., Laiwu 271100, China)

Abstract:In order to research the durability of recycled concrete mixed with slag-fly ash in the freeze-thaw and carbonation environment, 20% slag and 0%, 15%, 30% fly ash were simultaneously blended in the recycled concrete containing 100%   recycled coarse aggregate, and carbonation, freeze-thaw and freeze-thaw-carbonation coupling test were carried out. The degradation law of specimen compressive strength, mass loss rate, relative dynamic elastic modulus and carbonation depth changes was analyzed. The compressive strength model of slag-fly ash recycled concrete under the action of freeze-thaw-carbonation coupling was established. The results show that the frost resistance of recycled concrete is best, when the content of fly ash is 15% in recycled concrete, at the same time, the promoting effect of fly ash on the frost resistance of recycled concrete begins to weaken, when the freeze-thaw cycles are more than 100 times. The more fly ash content, the weaker the anti-carbonization performance of recycled concrete, and the carbonization depth is twice as much as that of recycled concrete without fly ash when the fly ash content is 30%. In the regenerated coarse aggregate coupling compressive strength environment, the freeze-thaw effect promotes the growth of carbonation depth, and the carbonization accelerates the freeze-thaw damage of slag-fly ash recycled concrete. The established slag-fly ash recycled concrete freeze-thaw-carbonization coupling compressive strength model can better reflect the degradation law of compressive strength under the freeze-thaw-carbonization coupling environment.

Keywords:freeze-thaw cycle; carbonization; content of  fly ash; recycled coarse aggregate;  freeze-thaw-carbonization coupling effect; durability; compressive strength model

*國(guó)家自然科學(xué)基金項(xiàng)目(51868061）;內(nèi)蒙古自然科學(xué)基金項(xiàng)目（2020MS05071）。

作者簡(jiǎn)介：王晨霞，博士，副教授，Email: wangchenxia77 @qq.com; 通訊作者：曹芙波，博士，教授，Email：caofubo@139.com。