Construction and Demolition Waste as Recycled Aggregates in Alkali-Activated Concretes

被引：43

作者：

Abdollahnejad, Zahra ^{[1
]}

Mastali, Mohammad ^{[2
]}

Falah, Mahroo ^{[2
]}

Luukkonen, Tero ^{[2
]}

Mazari, Mehran ^{[3
]}

Illikainen, Mirja ^{[2
]}

机构：

[1] Univ Connecticut, Civil & Environm Engn Dept, 261 Glenbrook Rd,Unit 3037, Storrs, CT 06269 USA

[2] Univ Oulu, Fac Technol, Fibre & Particle Engn, POB 4300, Oulu 90014, Finland

[3] Calif State Univ Los Angeles, Dept Civil Engn, Los Angeles, CA 90032 USA

来源：

MATERIALS | 2019年 / 12卷 / 23期

关键词：

alkali-activated concrete; recycled aggregate; construction and demolition waste; sustainability; ASH GEOPOLYMER CONCRETE; FLY-ASH; MECHANICAL-PROPERTIES; COARSE AGGREGATE; PHYSICOCHEMICAL PROPERTIES; MICROSTRUCTURAL ANALYSIS; DURABILITY PROPERTIES; COMPRESSIVE STRENGTH; BUILDING-MATERIALS; DRYING SHRINKAGE;

D O I：

10.3390/ma12234016

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The growth of global construction has contributed to an inevitable increase in the amount of construction and demolition (C&D) waste, and the recycling of C&D waste as aggregates in concrete is receiving increased interest, resulting in less demand for normal aggregates and bringing a potential solution for the landfilling of wastes. Recently, several studies have focused on the use of C&D waste in alkali-activated concrete to move one step closer to sustainable concretes. This paper focuses on the main mechanisms of using C&D waste in the resulting physical, mechanical, and durability properties of alkali-activated concrete in fresh and hardened state properties. The main difficulties observed with recycled aggregates (RA) in concrete, such as high levels of water demand, porous structure, and low mechanical strength, occur in RA alkali-activated concretes. These are associated with the highly porous nature and defects of RA. However, the high calcium concentration of RA affects the binder gel products, accelerates the hardening rate of the concrete, and reduces the flowability of alkali-activated concretes. For this reason, several techniques have been investigated for modifying the water content and workability of the fresh matrix and for treating RA and RA/alkali-activated binder interactions to produce more sustainable alkali-activated concretes.

引用

页数：22

共 130 条

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