Effects of Recycled Fine Aggregates and Inorganic Crystalline Materials on the Strength and Pore Structures of Cement-Based Composites

Sung-Ching Chen,Hui-Mi Hsu,Si-Yu Zou

doi:10.3390/cryst11060587

Sung-Ching Chen, Hui-Mi Hsu + Show 1 more

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https://doi.org/10.3390/cryst11060587

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Abstract

Concrete is porous; the partial pores in the internal structure of concrete are generated by hydration products, such as calcium hydroxide, dissolved in water. External harmful substances in the form of gases or aqueous solutions can penetrate concrete. The destruction of the internal structure of concrete leads to problems such as shortening of the service life of concrete as well as the corrosion and poor durability of steel. To improve the pore structure of concrete, a material can be added to concrete mixtures to cause the secondary hydration of the hydration products of cement. This reaction is expected to reduce the pore volume and increase the density of concrete. For existing concrete structures, inorganic crystalline materials can be used to protect the surface and reduce the intrusion of external harmful substances. In this study, the water–binder ratio was 0.4 and 0.6. Three inorganic crystalline materials and recycled fine aggregates (0%, 10%, 20%, and 30% replacement of natural aggregates by weight) were used in the same cement-based composites. The results indicated that all specimens had a high total charge-passed value, and inorganic crystalline material C provided superior protection for green cement-based composites.

Highlights

Concrete is currently the most widely used construction material; its service life varies in different environments
When the water–binder ratio was low, C was used as a coating material and recycled fine material was used to replace 0%
The compressive strength was higher at a low water–binder ratio than at a high water–binder ratio for all the test groups

Summary

Introduction

Concrete is currently the most widely used construction material; its service life varies in different environments. Long-term corrosive environments containing materials such as carbon dioxide, chloride, and sulfate can damage or deteriorate concrete [1,2,3,4,5,6,7]. Steel corrosion is a common failure phenomenon observed in concrete structures. Maintenance and reinforcement technology for concrete structures is a crucial topic in construction engineering. The unsuitable repair of concrete structures affects the social and economic development of an area as well as human safety. The main hazards of concrete cracks are affecting the bearing capacity and safety of the structure, affecting the waterproof of the structure, and affecting the durability and service life of the structure

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