SURFACE TREATMENT OF HYDRATED CEMENT PASTE USING "XYPEX" . PROTECTION OF CONCRETE. PROCEEDINGS OF THE INTERNATIONAL CONFERENCE HELD AT THE UNIVERSITY OF DUNDEE, SEPTEMBER 11-13, 1990

The use of XYPEX, a pore blocking active surface treatment which may be applied to existing structures, is described. Poor quality cement paste samples were water cured for 4 weeks and subsequently conditioned for a further 18 weeks at 88% relative humidity (rh). Samples were treated with Xypex and conditioned at approximately 100% RH for periods up to 26 weeks prior to assessment. This was performed using propanol counter diffusion, chloride diffusion and water permeability. Pore structure was characterised using propanol adsorption. Results show that Xypex reacts rapidly in the substrate, yielding improvements to the engineering properties. However, this assessment is test dependent. Comparison with published data suggests that the application of Xypex is equivalent to a reduction in water content from 0.8 to approximately 0.5. (Author/TRRL)