Fracture properties and acoustic emission characteristics of manufactured sand recycled fine aggregate concrete

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics Pub Date : 2024-08-27 DOI:10.1016/j.tafmec.2024.104633

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Abstract

To promote the application of recycled fine aggregates, fracture characteristics of concrete beams containing manufactured sand (MS) and recycled fine aggregate (RFA) were investigated. The fracture properties and acoustic emission (AE) characteristics of manufactured sand recycled fine aggregate concrete (MSRFAC) with 0 %, 25 %, 50 %, 75 % and 100 % RFA replacement rates were evaluated by three-point bending test of single-sided notched beams. The fracture mechanisms of MSRFAC beams were explored using AE and digital image correlation (DIC) techniques, and fracture process zone (FPZ) was qualitatively and quantitatively analyzed. The results indicated that the critical nominal stiffness, initial fracture toughness, fracture energy and characteristic length of MSRFAC decreased significantly with the increase of RFA replacement rate, up to 20.2 %, 37.7 %, 22.8 %, and 26.6 %, respectively, while the unstable fracture toughness was insensitive to the variation of RFA. Moreover, the AE activity, the tensile crack, large-scale crack, high amplitude, and high peak frequency in MSRFAC increased with increasing RFA replacement rate. According to the FPZ characteristics of MSRFAC, its FPZ length increased with the increase of RFA replacement rate, while the FPZ width decreased with the increase of RFA replacement rate. The critical FPZ lengths of MSRFAC with different RFA replacement rates were about 20.2–30.0 mm, and the maximum FPZ widths were about 26.0–36.7 mm. The RFA weakened the friction mechanism and interlocking effect between aggregates of MSRFAC, resulting in a faster FPZ propagation rate and smaller damage width of MSRFAC than normal manufactured sand concrete.

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人造砂再生细骨料混凝土的断裂性能和声发射特性

为了促进再生细骨料的应用，研究人员对含有人工砂（MS）和再生细骨料（RFA）的混凝土梁的断裂特性进行了调查。通过对单边缺口梁进行三点弯曲试验，评估了人造砂再生细骨料混凝土（MSRFAC）在 RFA 替代率为 0 %、25 %、50 %、75 % 和 100 % 时的断裂特性和声发射（AE）特征。使用 AE 和数字图像相关（DIC）技术探讨了 MSRFAC 梁的断裂机制，并对断裂过程区（FPZ）进行了定性和定量分析。结果表明，随着 RFA 替代率的增加，MSRFAC 的临界名义刚度、初始断裂韧性、断裂能和特征长度显著降低，分别降低了 20.2%、37.7%、22.8% 和 26.6%，而不稳定断裂韧性对 RFA 的变化不敏感。此外，随着 RFA 替代率的增加，MSRFAC 的 AE 活性、拉伸裂纹、大尺度裂纹、高振幅和高峰值频率也随之增加。根据 MSRFAC 的 FPZ 特性，其 FPZ 长度随 RFA 置换率的增加而增加，而 FPZ 宽度则随 RFA 置换率的增加而减小。不同 RFA 替代率下 MSRFAC 的临界 FPZ 长度约为 20.2-30.0 mm，最大 FPZ 宽度约为 26.0-36.7 mm。与普通人工砂混凝土相比，RFA 削弱了 MSRFAC 骨料之间的摩擦机制和连锁效应，导致 MSRFAC 的 FPZ 扩展速度更快，破坏宽度更小。

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

Theoretical and Applied Fracture Mechanics 工程技术-工程：机械

CiteScore

8.40

自引率

18.90%

发文量

435

审稿时长

37 days

期刊介绍： Theoretical and Applied Fracture Mechanics'' aims & scopes have been re-designed to cover both the theoretical, applied, and numerical aspects associated with those cracking related phenomena taking place, at a micro-, meso-, and macroscopic level, in materials/components/structures of any kind. The journal aims to cover the cracking/mechanical behaviour of materials/components/structures in those situations involving both time-independent and time-dependent system of external forces/moments (such as, for instance, quasi-static, impulsive, impact, blasting, creep, contact, and fatigue loading). Since, under the above circumstances, the mechanical behaviour of cracked materials/components/structures is also affected by the environmental conditions, the journal would consider also those theoretical/experimental research works investigating the effect of external variables such as, for instance, the effect of corrosive environments as well as of high/low-temperature.