Properties of Non-Structural Concrete Made with Mixed Recycled Aggregates and Low Cement Content.

Antonio López-Uceda,Jesús Ayuso,Martin López,José Jimenez,Francisco Agrela,María Sierra

doi:10.3390/ma9020074

Antonio López-Uceda, Jesús Ayuso + Show 4 more

Open Access

https://doi.org/10.3390/ma9020074

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Abstract

In spite of not being legally accepted in most countries, mixed recycled aggregates (MRA) could be a suitable raw material for concrete manufacturing. The aims of this research were as follows: (i) to analyze the effect of the replacement ratio of natural coarse aggregates with MRA, the amount of ceramic particles in MRA, and the amount of cement, on the mechanical and physical properties of a non-structural concrete made with a low cement content; and (ii) to verify if it is possible to achieve a low-strength concrete that replaces a greater amount of natural aggregate with MRA and that has a low cement content. Two series of concrete mixes were manufactured using 180 and 200 kg/m3 of CEM II/A-V 42.5 R type Portland cement. Each series included seven concrete mixes: one with natural aggregates; two MRA with different ceramic particle contents; and one for each coarse aggregate replacement ratio (20%, 40%, and 100%). To study their properties, compressive and splitting tensile strength, modulus of elasticity, density, porosity, water penetration, and sorptivity, tests were performed. The results confirmed that the main factors affecting the properties analyzed in this research are the amount of cement and the replacement ratio; the two MRAs used in this work presented a similar influence on the properties. A non-structural, low-strength concrete (15 MPa) with an MRA replacement ratio of up to 100% for 200 kg/m3 of cement was obtained. This type of concrete could be applied in the construction of ditches, sidewalks, and other similar civil works.

Highlights

Most of the CO2 -equivalent produced to manufacture concrete comes from cement production; over 400 kg of CO2 -equivalent is generated per m3 of concrete [1,2], and is responsible for 5%of all anthropogenic CO2 emissions [3]
The objectives of this work were as follows: (i) to analyze the mechanical and physical properties of a non-structural concrete made with mixed recycled aggregates (MRA) and a low cement content, and to study the effect
Based on the results obtained in this study, substitution percentage of MRA in the coarse fraction

Summary

Introduction

Most of the CO2 -equivalent produced to manufacture concrete comes from cement production; over 400 kg of CO2 -equivalent is generated per m3 of concrete [1,2], and is responsible for 5%of all anthropogenic CO2 emissions [3]. Most of the CO2 -equivalent produced to manufacture concrete comes from cement production; over 400 kg of CO2 -equivalent is generated per m3 of concrete [1,2], and is responsible for 5%. In the European Union, 900 million tonnes of cement were produced in 2008 [4]. CO2 equivalent emissions reached 101 million tonnes in the cement production sector [5]. This results in a high contribution to the emission of greenhouse gases, and contributes greatly to global warming. The recycling and reuse of CDW in new building materials require less energy consumption, reduce CO2 equivalent emissions, and, as a result, benefit the environment

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