Does carbonation affect the microstructural inhomogeneity of recycled aggregate concrete?

IF 6.7 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Journal of building engineering Pub Date : 2024-12-24 DOI:10.1016/j.jobe.2024.111650

Renjie Mi, Ganghua Pan, Feifei Zhou

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引用次数: 0

Abstract

In this study, two types of modelled recycled aggregate concrete were prepared using the recycled aggregates in the lab. The evolutions of three kinds of interfacial transition zones (ITZs) and two kinds of mortars in these concretes before and after accelerated carbonation were separately studied using phenolphthalein spray test, CO2 diffusion coefficient modelling, pore structure test, backscattered electron test and nanoindentation test. The results showed that carbonation increased the inhomogeneity of recycled aggregate concrete by dividing the concrete into an irregular carbonation zone and a noncarbonation zone. Additionally, the average ITZ width showed the highest difference before and after carbonation, compared with the average elasticity modulus, average unhydrated cement content and average porosity. Carbonation also changed the differences in the microstructures between different kinds of ITZs and between different types of mortars. The inhomogeneity changes with time in the whole service life and further affects the long-term mechanical properties and durability of recycled aggregate concrete.

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碳化会影响再生骨料混凝土的微观结构不均匀性吗？

在本研究中，利用再生骨料在实验室中制备了两种类型的再生骨料模型混凝土。通过酚酞喷雾试验、CO2扩散系数模拟、孔隙结构试验、背散射电子试验和纳米压痕试验，分别研究了加速碳化前后混凝土中3种界面过渡区（ITZs）和2种砂浆的演变规律。结果表明：碳化使再生骨料混凝土分成不规则碳化区和非碳化区，增加了再生骨料混凝土的不均匀性；与平均弹性模量、平均不水化水泥含量和平均孔隙度相比，碳化前后的平均ITZ宽度差异最大。碳化作用还改变了不同类型砂浆和不同类型砂浆之间微观结构的差异。这种不均匀性在整个使用寿命中随时间而变化，进而影响再生骨料混凝土的长期力学性能和耐久性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of building engineering Engineering-Civil and Structural Engineering

CiteScore

10.00

自引率

12.50%

发文量

1901

审稿时长

35 days

期刊介绍： The Journal of Building Engineering is an interdisciplinary journal that covers all aspects of science and technology concerned with the whole life cycle of the built environment; from the design phase through to construction, operation, performance, maintenance and its deterioration.