Determination of the efficacy of surface treatments on porous building materials.

This thesis describes the mechanisms by which concrete and stone deteriorate and some of the surface treatment types available. Test techniques which have the potential to assess surface treatments' efficacy and/or presence are described. These techniques were then assessed, and from this, a suite of tests for use on site was put together. The suite comprised techniques able to measure: water absorption; electrical resistivity; moisture content; surface reflectance. A number of tests were also used exclusively in the laboratory to confirm the presence of a surface treatment and to obtain a better understanding of the mechanisms of water and treatment ingress. These techniques were: scanning electron microscopy; pore size distribution; total porosity. The suite of tests were then fully assessed under laboratory and site conditions on various substrate materials and surface treatment types. A complex inter-relationship between all the test techniques and surface conditions at the time of test was found to exist. With the use of the suite of tests it was possible to distinguish between untreated and treated surfaces, and to identify partly effective surface treatments