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(中鐵十八局集團(tuán)第二工程有限公司， 唐山 063000)

［摘要］針對(duì)不同因素對(duì)再生混凝土性能的影響問(wèn)題，設(shè)計(jì)正交試驗(yàn)測(cè)試不同水膠比、再生粗細(xì)骨料摻和比例、粉煤灰摻和比例的再生混凝土的工作性能和力學(xué)性能。確定再生混凝土的最優(yōu)配比，測(cè)試該再生混凝土的耐久性，并將其與工作性能、力學(xué)性能相近的C40普通混凝土進(jìn)行對(duì)比，通過(guò)SEM觀測(cè)其內(nèi)部結(jié)構(gòu)，通過(guò)壓汞法分析其孔隙結(jié)構(gòu)。結(jié)果表明：再生混凝土強(qiáng)度影響大小順序?yàn)樵偕止橇蠐胶捅壤?gt;水膠比>再生細(xì)骨料摻和比例>粉煤灰摻和比例；再生混凝土坍落度影響大小順序?yàn)樵偕止橇蠐胶捅壤?gt;粉煤灰摻和比例>水膠比>再生細(xì)骨料摻和比例；由于再生粗骨料存在微裂縫，再生混凝土耐久性稍弱于普通混凝土；加大混凝土保護(hù)層厚度，增加礦物摻合料摻和比例可以改善再生混凝土耐久性；觀察SEM圖像可以看到，再生骨料-水泥石界面粘結(jié)性質(zhì)較好，但再生骨料表面有一些微裂縫，分析壓汞法結(jié)果發(fā)現(xiàn)，再生混凝土中100～1 000nm范圍內(nèi)的孔隙數(shù)量較多，不利于再生混凝土的耐久性。

［關(guān)鍵詞］再生混凝土；正交試驗(yàn)；耐久性；孔結(jié)構(gòu)；壓汞法

中圖分類(lèi)號(hào)：TU528-79文獻(xiàn)標(biāo)識(shí)碼：A文章編號(hào)：1002-848X(2021)09-0074-05

Analysis of influencing factors on performance of recycled concrete and research on its durability

PENG Yongjun

(China Railway Eighteenth Bureau Group Second Engineering  Co., Ltd., Tangshan 063000, China)

Abstract:In view of the influence of different factors on the performance of recycled concrete, orthogonal tests were designed to test the working and mechanical properties of recycled concrete with different water-binder ratios, mixing ratios of recycled coarse and fine aggregate and fly ash. The optimum mixing ratio of recycled concrete was determined, and the durability of the recycled concrete was tested. The durability of the recycled concrete was compared with that of C40 ordinary concrete with similar working and mechanical properties, and its internal structure was observed by SEM and the pore structure was analyzed by mercury injection method. The results show that: the influence order of recycled concrete strength is recycled coarse aggregate mixing ratio>water-binder ratio>recycled fine aggregate mixing ratio>fly ash mixing ratio; Recycled concrete slump influence order is recycled coarse aggregate mixing ratio>fly ash mixing ratio>water-binder ratio>recycled fine aggregate mixing ratio; The durability of recycled concrete is weaker than that of ordinary concrete.Increasing the thickness of the concrete protective layer and the minerals mixing ratio can improve the durability of recycled concrete; By observing SEM images, the interfacial adhesion between recycled aggregate and cement paste is good but there are some micro cracks on the surface of recycled aggregate. By analyzing the results of mercury injection method, it is found that there are many fine pores in recycled concrete 100～1 000nm, which directly affects the durability of concrete.

Keywords:recycled concrete; orthogonal test; durability; pore structure; mercury injection

作者簡(jiǎn)介：彭勇軍，學(xué)士，高級(jí)工程師，Email：809897249@qq.com。