Vlasta Ondrejka Harbulakova , Adriana Estokova , Alena Luptakova , Simona Korenova

Study of durability of fibrous cement based materials exposed to microorganisms

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Abstract

Fibrous cement based materials belong to the main long-lasting building materials. Few building materials offer a combination of architectural scope and strong technical specification as convincing as fibrous cement based materials e.g. cladding and roofing. One of the most desirable qualities of fibrous cement based board is its durability due to its ability to resist all kinds of weather conditions. Frost and thaw, heat, hale or rain does not pose a threat to fibrous cement based materials. Unlike wood siding, fibre board siding doesn't rot or require frequent repainting. Inside buildings fibrous cement based materials are applied as backer board in wet areas or for dry walls in heavy duty applications where fire resistance and strength are the dominant requirements. The paper is primarily concerned with fibrous cement based specimens’ microbially influenced under laboratory conditions during 3 months. In the experiment, sulphate-reducing bacteria (SRB) genera Desulfovibrio spp. and sulphur-oxidising bacteria Acidithiobacillus thiooxidans were used. The role of bacteria mentioned above has been linked to the generation of biogenic sulphuric acid resulting in corrosion process by dissolution of calcium containing minerals from the matrices of building materials. Cement fibres boards exposed to simultaneous deleterious effect of bacteria were evaluated by weight and surface changes of the specimens and pH values changes in leachates.

Keywords:fibre-cement; composites; sulphur-oxidising bacteria; sulphate-reducing bacteria.