Physical characterization and alkali carbonate reactivity (ACR) potential of the rocks from Bauhti Pind and Bajar area Hassan Abdal, Pakistan

Abstract

This study is conducted to evaluate aggregate characteristics and alkali carbonate reactivity (ACR) potential of carbonate rocks of the Bouhti Pind and Bajar area, Hassan Abdal, Pakistan. Physical and chemical tests were performed to assess aggregate suitability. Mean specific gravity (2.65-2.65), water absorption (0.51-0.68%), Los Angeles abrasion (24.78-26.10%) and sulphate soundness values (2.86-4.25%) of the carbonate rocks of these areas are within specified limits of their respective standards. Petrographic studies of Bajar area reveal the presence of 96.3% calcite, 2% clays, 1% hematite and 0.7% quartz. These rocks do not contain dolomite and show no expansion in rock cylinder test. Therefore, the aggregate is not prone to ACR and can be used in cement concrete. Rocks of Bouhti Pind area have mean 92% calcite, 3.8% dolomite, 2% clays, 1.2% hematite and 1% monocrystalline quartz. The amount of deleterious minerals specifically dolomite and clays are below the maximum allowed limit to initiate ACR. However, one of the rock cylinders shows 0.043% expansion which is below threshold limit of 0.10% to cause ACR as specified in ASTM C-585. Hence, these carbonate rocks qualify physical characterization and ACR tests and can be used in the construction of roads and in cement concrete.

Exploring the potential of late permian aggregate resources for utilization in engineering structures through geotechnical, geochemical and petrographic analyses

“…There are several factors that influence the physical properties of rocks, including the composition of the modal minerals, the cement, the grain size, and the contact between grains 52 . Similarly, the physical and petrographic attributes of sedimentary rocks have a significant influence on their mechanical characteristics 9 , 52 , 57 . Some geotechnical analyses performed are correlated to understand the physico-mechnaical properties of the rock units.…”

“…These physicomechanical and petrographic characteristics may be affected by the mineral contents, hardness, chemical stability, porosity, and composition. It is important to analyze the petrography of aggregates in order to identify its texture, mineralogy, bioclasts, matrix type, microfractures, and texture type 9 . Some scholars have examined and made predictions about the engineering qualities of aggregates based on their petrographical and physical characteristics 6 , 10 .…”