Influence of High Temperatures on Surface Cracking of Concrete Studied by Image Scanning Technique

Surface concrete cracking is a visible type of damage that has significantly adverse effects on the mechanical properties and durability properties of concrete. This paper presents an experimental study on the identification and quantification of surface cracking of concrete heated to different temperatures ranging from 105 to 1250ºC. In addition to the quantification of the residual compressive strengths of concrete after high temperature exposure, both initial surface absorption and total porosity were measured. The crack density was determined using a flat bed scanner and then images were treated using paint shop pro program. The total porosity was obtained using ASTM boiling. The mechanical properties of concrete were largely affected by temperatures beyond 500°C and were very feeble when temperatures exceeded 1000°C. The surface cracks' density, initial surface absorption and total porosity by boiling methods gave a rapid indication on concrete durability.