Discussion on a Frost Susceptibility of Fiber Reinforced Cement Building Materials Based on the Three Dimensional Pore Structure

Abstract

Frost susceptibility of cement boards being reinforced with fibers (FRCB) was discussed from the view point of a three dimensional connecting structure of pores. It was found that the complexity in an interconnection of pores, indicating the degree of a spacial branching of pores, has decisive effects on the frost susceptibility of the FRCB materials, likewise as in the case of the fired clay roofing tiles and the fired bricks. Such higher complexity in the three dimensional pores branching structure brings much amount of unfrozen water which is entrapped in the pores structure during cooling. Resultantly, the hydraulic pressure due to freezing of the entrapped water causes a structural damage of the materials. It was found that the water absorption correlates strongly with the frost damage on the FRCB materials, in despite of rather poor correlation on the materials of fired clay roofing tiles and the bricks.