The effect of the textural characteristics on the engineering properties of the basalts from Yozgat region, Turkey

Abstract

Engineering properties of rocks vary as they are heterogeneous materials by nature because of mineralogical composition, texture, porosity, and alteration, etc. This study focuses on the investigation of the relationship between internal structure and engineering parameters of basalt samples by digitizing the textural properties. Thin sections studies of basalts were made into three groups: aphanitic, amygdaloidal, and vesicular on the basis of texture. Further, the textural properties were digitized in thin sections and the texture coefficient (TC) of each group was calculated. Uniaxial compressive strength, dry unit weight, point load strength index, Schmidt hammer rebound, and P-wave velocity of the samples were determined in the laboratory. Simple regression analyses were performed using the laboratory results incorporating first TC and engineering parameters and the second phase of the analysis focused on the relationship between uniaxial compressive strength and the rest of the parameters of samples with different texture coefficients. The highest texture coefficient was found to be 0.50 in aphanitic basalts while vesicular basalts have the lowest TC of 0.37. As the TC increases, rock strength increases. Strong-very strong correlations between uniaxial compressive strength and the rest of the engineering parameters of aphanitic and amygdaloidal-basalts with a TC of 0.50 and 0.45 are in agreement with the findings in the literature while there are no meaningful correlations between uniaxial strength and the aforementioned parameters except dry unit weight in vesicular basalts. These results indicate that the presence of empty pores in vesicular basalts reduced the uniaxial compressive strength and TC by increasing the heterogeneity.