Description: Sealants are widely used in the water industry to prevent water leakage through designed joints and repaired cracks. The extent and rate of microbiological deterioration can be critical, for example in terms of water contamination in service reservoirs, and sealant breakdown where the fluid is heavily loaded with a wide variety of micro-organisms (such as in sewage treatment applications). This report focuses on the degradation of civil engineering polymeric sealants under aqueous challenge conditions, using an evaluation procedure devised to assess the susceptibility of a sealant formulation to microbiological degradation. C520 will enable sealant end-users to obtain a greater awareness of the influence of micro-organisms and be better informed about the essential test data from sealant manufacturers. Various sealant formulations were prepared as strips and joints, and challenged with defined mixtures of microorganisms and selected water industry environments. The assessment of sealant compromise was based upon tensile testing using modulus and extensibility as the performance indices, as shown by modification of the surface topography. From these data, a substantial reference database has been obtained which permits comparison of the performance of different sealant formulations against defined microbial consortia and, by extrapolation, to their performance in particular environments. Sealants - microbiological deterioration under wet conditions will be of interest to design, specification, materials, construction supervising and operation engineers involved in the water industry.

Keywords: design and buildability, materials, water infrastructure, dams and reservoirs, sewerage, construction management, water quality.

Contents: 1 Introduction, 2 Sealant composition and microbial degradation, 3 Test procedures, 4 Experimental data and interpretation, 5 General discussion, 6 Summary, recommendations and future work, 7 Research data summaries, 8 References, Appendices