PHYSICAL-PROPERTIES AND INDIRECT ESTIMATION OF MICROFRACTURES USING NIGERIAN CARBONATE ROCKS AS EXAMPLES

The performance of rocks as construction materials are essentially controlled by their physical properties, which are partly related to microfractures. Therefore, the assessment of the degree of microfracturing cannot be overemphasised, especially when rock specimens are products of blasting from quarries. In this paper, three parameters are used to establish relationships, i.e., the porosity index, n(i), defined as the ratio of effective-to-total porosity; the swelling index, s(i), defined as the ratio of the change in length between a dry and a saturated rock specimen to the original length of the specimen, and the uniaxial compressive strength. Results show that compressive strength decreases with increasing porosity and swelling indices; the swelling index increases with increasing porosity index. These relationships are then used as a basis to, indirectly, estimate the degree of microfracturing.