Measurement of Surface Damage through Boundary Detection: An Approach to Assess Durability of Cementitious Composites under Tannery Wastewater

Tanvir Manzur,Samira Mahmud,Sinha Lamia Sultana,Khaled Mahmood Ehsan

doi:10.1155/2016/5368635

Abstract

Concrete structures are often subjected to aggressive aqueous environments which consist of several chemical agents that can react with concrete to produce adverse effects. A Central Effluent Treatment Plant consisting of reinforced concrete structures which is being constructed at Savar, Bangladesh, is an example of such a case. The purpose of this treatment facility is to reduce the environmental pollution created by tannery wastewater. However, tannery wastewater consists of several chemicals such as sulfates, chlorides, and ammonium, which, from the literature, are known to generate detrimental effects on concrete. Evaluation of durability of concrete structures in such environments is therefore imperative. This paper highlights a technique of boundary detection developed through image processing performed using MATLAB. Cement mortar cubes were submerged in simulated tannery wastewater and the images of the surface of cubes were taken at several time intervals. In addition, readings for compressive strength and weight were also taken on the same days. In this paper, an attempt is made to correlate the results from image processing with that of strength and weight loss. It was found, within the scope of this study, that the specimens which suffered greater strength and weight loss also underwent greater loss of surface area.

Highlights

Durability of concrete structures is a matter of concern when the structure is exposed to harsh environmental conditions
Surface area loss determined by the proposed image processing technique is presented
This paper has described a method for evaluation of concrete degradation under tannery wastewater by employing an image processing technique

Summary

Introduction

Durability of concrete structures is a matter of concern when the structure is exposed to harsh environmental conditions. Assessing the durability of an existing concrete structure in such conditions is neither a very straightforward nor a simple task. It is rather complex, as several factors have a controlling effect on the behavior of concrete and because no direct measurement of durability can be acquired. This paper aims to provide a directive regarding the durability of concrete in tannery wastewater. The proportions of constituents were determined from the analysis of collected field samples of tannery wastewater. The findings of this study depict the behavior of concrete when exposed to tannery wastewater composed of these constituents. The use of this technique could be useful when a prompt analysis is required to get a primary idea about the extent of degradation, before pursuing a more detailed study based on which mitigation measures may be employed

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