A research into intrinsic parameters material to the durability of highly porous building stones

Abstract

This chapter describes the research conducted to study the main characteristics that influence the changes in highly porous stone materials and the parameters that most clearly quantify this degradation. Two blocks of quarry carparo (highly porous calcarenite) from Casalabate and Gallipoli were used. The laboratory study was carried out by examining their characteristics before and after artificial aging. Observations by optical microscopy, X-ray diffraction (XRD) analyses, porosimetric measurements, permeability and evaporation tests, absorption by capillarity and immersion tests, and measurement of ultrasonic wave velocity were carried out on samples from quarries. The same samples were then exposed to artificial aging with sodium sulfate, which effectively produced deterioration comparable with the "in situ" calcarenite stones. All the measurements that were carried out before aging procedure were repeated on the samples. On examination of the results obtained, the porosimetric analysis and the petrographic analysis on thin section provided best conclusions in understanding the diverse reaction of materials to this type of weathering. From the analyses, it can be concluded that pore size distribution and textural characteristics of cement are not quantifiable to the deterioration measurement because of its superficial location. On the contrary, the most significant parameter for the evaluation of durability is weight variation because of loss material.