Water penetration into strain hardening cementitious composites before and after water-repellent surface impregnation

Strain Hardening Cementitious Composites (SHCC) are a comparatively young group of cement-based fiber reinforced materials with high strain capacity. The strain capacity of SHCC, however, is due to multi-crack formation. Water penetration into SHCC in the unloaded state and under tensile stress was observed with neutron radiography. It has been shown that water penetration into SHCC under tensile load can be significantly reduced by adding a water repellent agent to the fresh mix. Surface impregnation with a water repellent agent is an alternative method to reduce water penetration into cracked SHCC. The effectiveness of both methods was checked by neutron radiography. Integral water repellent treatment reduces water penetration significantly but water penetrates into wide cracks nevertheless. It could be shown that surface impregnation with silane gel, however, prevents water penetration.