Experimental Verification of Behavior of Glass and Carbon Fibers in Alkali Environment

The paper discusses durability of glass and carbon fibers which are exposed to alkali environment of concrete. Mainly glass fibers are affected by the high alkali environment with pH of concrete exceeding 12.0. The degradation of fibers is reflected by decreasing of its tension strength, while the rate of decreasing is depended on exposition time and temperature. The paper briefly presents results of a large experimental investigation which should specify an influence of alkali ions concentration in a solution on reduction of the mechanical properties of fibers. Reference samples were immersed in a bath with distilled water and the others were stored at ambient air only.