Quantification and estimation of the durability of stones used as construction material more precisely by modification of static rock durability index

Abstract

The correct classification of the durability of rocks used as construction material is extremely important, as it directly affects their service life in engineering projects. For this reason, various durability determination methods for stones have been suggested by previous studies. Among them the static rock durability index seems more comprehensive in terms of the input parameters used. However, some studies show that the data obtained from the static rock durability index method may give inconsistent results, especially for moderate- to low-durability rocks like andesite and tuff as indicated by their accelerated weathering test results and long-term field performances. Therefore, to increase the sensitivity of the static rock durability index method and to be able to assess the durability of rocks more precisely, some modifications were carried out on the input parameters of the static rock durability index method and a new durability evaluation method named ‘Modified Static Rock Durability Index’ (MRDIs) was suggested. By using the ratio of wet to dry uniaxial compressive strength, Böhme abrasion value, water absorption by weight, dry surface saturated unit volume, weight loss after salt crystallization and the number of cycles causing total disintegration of sample during the Na2SO4 salt crystallization test as input parameters, the sensitivity of the static rock durability index was increased especially for moderate- and low-durability stones like andesite and tuff.As a result, the durability of six volcanic rocks like andesite and tuff evaluated in this study can be classified precisely with the MRDIs method compatible to the durability properties obtained from the accelerated weathering tests. In addition, the MRDIs method was tested using the data relating to the material properties of andesites and tuffs whose long-term field performances were specified in the literature and compatible results were obtained with their field performances in terms of durability.