Investigation of the Effect of Microcapsule Additive on Mechanical and Physical Properties of Concrete

Reem Salmana,Farhad Othman,Alaa Abdul-Hamead

doi:10.30684/etj.v39i11.2091

Abstract

Cracks are a fundamental problem in concrete, so this research investigates an experimental study of the effect of adding SiO2 on the self-healing behaviour of concrete. The study is done by studying the physical properties, microstructure, and mechanical properties of concrete. Microcapsules were prepared to contain (cement and nano SiO2) in a (palettization (fluidize bed coating) method) with (5,10, and 15) % of cement weight. The ratio of the prepared concrete mixture was (1: 2: 4) and the ratio of water to cement (W / C) 0.45 by the weight of cement was also added as 0.6% Superplasticizer to all concrete mixtures. SiO2 MC is added with (2.5) % of the cement weight in the concrete mixture. In this study, porosity, density, and water absorption tests were performed to study the physical properties, compressive and bending strength to study mechanical properties. So, referring to the results, (SiO2 MC) was used as an effective effect in the self-healing cracking mechanism, and in improving the bending strength and compressive strength. Also, 10 % wt. was recorded as the best addition because it has a positive effect on properties to be applied in construction.

Highlights

Concrete structures are more susceptible to cracking, as we notice that small cracks have no effect on these structures, but the problem lies in the large cracks that cause the breakdown of concrete structures
The purpose of this study is preparing a concrete mixture suitable for concrete applications that can self-repair by adding different proportions of SiO2 micro capsules, in order to observe the effect of these capsules on the efficiency of selfhealing, by studying the physical and mechanical properties of them and to observe the slit-closing mechanism in the micro-capsule-containing samples compared to the standard sample
The improvement in strength of all samples can be attributed to the effect of the superplasticizer which, as a parameter, represents the lowest ratio of water to cement used in preparing the concrete mixture

Summary

Introduction

Concrete structures are more susceptible to cracking, as we notice that small cracks have no effect on these structures, but the problem lies in the large cracks that cause the breakdown of concrete structures. A new approach has been proposed to improve the physical and chemical properties of concrete and heal cracks. These materials can treat and improve the properties by producing precipitated crystals such as calcium carbonate [1]. Previous studies showed the positive effect when using silicon oxide nanoparticles as additives, according to Ali Haidari et al [4], where adding a small amount of (Nano SiO2) to the concrete improved its compressive strength and decreased its ability to absorb water and the physical properties of concrete. Many studies have used the micro-capsule technique and have noted a positive effect in treating cracks and improving the properties.

Objectives

Results

Conclusion