MICROSTRUCTURE DUBETON DESABLE

Density changes and also porosity were measured for a series of sand c oncrete specimens. It found that microstructure of material is homogen eous, amorphous with a perfect adhesion of sand particules in this mat rix. The investigation of observing replica of polished sand concrete specimens using scanning microscopy shows that the material is very li ttle cracked. This latter point is explained by the rate and essential ly by the uniformity of drying (uniformity occuring along external and internal fronts of the material sample) which leads to low hydric gra dients explaining then this feature. The kinetics of drying are very d ifferent from the behavior of ordinary concrete (very slow and non uni form). The porometry is fine and monomodal structure (single peak in t he pores histogramm), whereas that of ordinary concrete is bimodal (tw o peaks : one corresponding to micropores and the another to macropore s). The knowledge of the microstructure allows the establishment of th e simple structural models making it easy to deal with the behavior of the concrete.