Calcium Aluminate Cement for corrosion resistant sewer mortars and concretes

Microbiologically Induced Corrosion (MIC) causes severe concrete deterioration in pipelines, manholes and sewer structures. This process is caused by sulfuric acid producing bacteria which mainly occur in waste water systems. Mortar compositions containing Ordinary Portland Cements (OPC) and Calcium Aluminate Cement (CAC) have been selected for a MIC test. Workability and strength development of each mortar composition was determined prior to testing. Special prepared mortar cubes were then placed in an accelerated biogenic corrosion weathering chamber. Change in weight loss, specimen shape, surface pH and alterations of mortar cubes during 10-month testing were recorded. Different material properties regarding corrosion resistance between the two OPC mortars and the CAC mortar are evident.

1 Introduction

Sewage systems are used to collect the wastewater of cities and to transport them to sewage treatment plants. These systems are extensive and commonly made of concrete. Concretes and mortars used in pipelines and manholes of sewage systems are damaged by all kind of attacks (physical, chemical and thermal). MIC has been identified as the strongest form of degradation of concrete sewage systems worldwide and is caused by sulfuric acid producing bacteria from the genus thiobacillus and others, that grow in environments on concrete surfaces which offer favorable conditions (e.g....

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