Gis-Based Quarry Site Selection And Suitability Assessment Of The Rock For Concrete Aggregate: Case Study Of Adama Town

Abstract

Aggregates are construction materials derived from primary resources either by crushing sound rock (crushed stone aggregates) or naturally occurring unbound clastic sediments (natural sand and gravel aggregates). It is one of the main constituents of the construction industry. It is used to produce concrete, which is one of the versatile and widely used building materials in the construction industry. Consequently, the aggregate demand is escalating related to the rapid development of high-rise buildings, road & railway construction, etc. (Adinkrah-Appiah et al., 2016). They are produced by a process called quarrying, which is one of the processes that highly affect the environment, so for their production, a suitable quarry site that has less influence on the environment and that is economically feasible must be selected. Aggregate quality assessment is also important to ensure aggregate good performance for the intended use. This study aims to select a suitable quarry site that qualifies as a concrete aggregate for various construction projects in Adama town and surrounding areas. The most suitable quarry sites were identified by using integrated GIS and AHP approaches in two stages. In the first stage, the selection was carried out based on criteria that govern the economic and environmental aspects of the quarry site, such as land use and land-cover, distance to the built-up area, depth to ground water, distance to streams/water bodies, distance to roads, relative relief, and slope angle. Then, the suitable quarry sites were further refined, considering the availability of suitable lithology for aggregate. The result suggests that 72.5% of the study area is unsuitable, 0.53% of the study area has low suitability, 3.24% of the study area is moderately suitable, and 23.64% highly suitable for crushed stone aggregate. After the suitable sites were identified, rock samples were collected from highly suitable sites for quality assessment. Aggregate physical property tests; strength tests, including aggregate crushing value (ACV), Los Angeles abrasion value (LAAV), aggregate impact value (AIV); chemical characterization for soundness, and petrographical analysis were the parameters considered in the study. Based on the result, the ignimbrite rock Q1, the basalt rock in Q6, and the basalt rock in Q7 exhibit a remarkable quality that complies with the standard to be used as a crushed stone aggregate.