The effects of weathering on limestone used for building the cemetery wall in Tel Kaif-North Iraq

Abstract

The purpose of this study is to evaluate the impact of weathering on rocks used in construction during a defined period of these rocks. The field study involves weathering and rock strength measurements using a geological hammer. Laboratory testing for both wall limestone and fresh quarry limestone was performed to determine the bulk density, the porosity and absorption of water, and the durability test was performed for fresh quarry limestone. A polarized microscope and scan electron microscope, petrographic analysis has been conducted for various weathering rates. Field notes explain the moderate and high degree of weathering and low strength in the bottom of the wall, whilst the top is slightly weathered and high strength. Laboratory notes through stone crushing show a change from white to beige for slightly weathered samples to moderately and highly weathered samples in powder color. Increasing weathering reduces bulk density and insoluble residues, from 13% in non-weathered rocks to 25% in high-weathered rocks the level of insoluble residue increases. Water absorption in non-weathered rocks and high weathering rocks rises from 6% to 14% and porosity from 14% to 27% respectively. Durability tests show that calcarenite exceeds very high durability, high durability calcirudite and calcilutite, and moderately durable calcisiltite. Four types of porosity, intergranular, intragranular, mold and microfracture appear in the petrographic study using a polarized microscope. Clay minerals and iron oxides surrounding the pores appear in weathered specimens, not in fresh, calcite crystal oxidation and secondary calcite growth on the inner surface of voids have also been shown in the scanning of electron microscopes.