Sodium sulfate attack on Portland cement structures: experimental and analytical approach

Laís Cristina Barbosa Costa,Thais Mayra Oliveira,Michèle Cristina Resende Farage,Leonardo Goliatt Da Fonseca,João Mário Roque Escoqui

doi:10.1590/0370-44672018710009

Laís Cristina Barbosa Costa, Thais Mayra Oliveira + Show 3 more

Open Access

https://doi.org/10.1590/0370-44672018710009

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Abstract

Abstract The industrial development and the advance of the primary sector in Brazil generated an increase in the cases of structures damaged by sulfate attacks. A reduction in material lifetime is one of the most costly factors in the construction field. Therefore, it is necessary to understand the sulfate attack mechanism in order to provide repairs and prevent further attacks. This article aims to understand how the environmental condition and the material properties influence the attack’s severity. Hence, it combined an experimental program and analytical model to measure those parameter effects. Experiments show that cement with a higher amount of tricalcium aluminate (C3A), as the CP V ARI, presented a more pronounced deterioration. Visual changes such as cracking, crystallization of expansive products and a complete disintegration were also observed. In addition, loss of resistance occurred in the specimens with low slag content. Moreover, the model is useful to predict the delamination depth and to identify the most critical factors influencing the attack through sensitive analysis. Its results were compared with real cases based on literature and verifying the model reliability.

Highlights

There are several sources of sulfate, such as sewage, industrial waste, and fertilizers
The industrial development generated an increase in the cases of structures damaged by sulfate attacks
The visual effects caused by a sulfate attack are usually perceived first

Summary

Introduction

There are several sources of sulfate, such as sewage, industrial waste, and fertilizers. One of the most costly factors in the construction field is the reduction of material lifetime. Because this type of deterioration process is complex, it has raised many controversial theories in order to understand its mechanism (Santhanam et al, 2001; Neville, 2004). The attack mechanism is complex, since there are numerous factors that influence the severity of the process. These factors can be related to the material’s nature (w/c ratio, cure process, clinker constitution, additions and so on) and to the surrounding environmental circumstances (temperature, pH, external sulfate concentration, cyclic exposure and so on)

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