The quality of aggregates affects the durability and performance of pavement as it is the dominant component both in rigid and flexible pavement. Hence, aggregate quality assessment is important to ensure the good performance of aggregate in different sections of pavements. The present work aims to assess the suitability of limestone for road aggregate. Thirty-seven Mesozoic limestone samples obtained from previously identified suitable quarry sites were subjected to petrographic and geotechnical analyses. Physical properties (ultrasonic pulse velocity (PVU), water absorption (Wa), Na2SO4 soundness, and specific gravity tests) and mechanical properties (unconfined compressive strength (UCS), Aggregate crushing value (ACV), Aggregate Impact Value (AIV), and Los Angles Abrasion value (LAAV)) were determined in the lab and then compared with the globally accepted standards. The petrographic observations revealed that the Mesozoic limestones of the area are dominantly composed of micrite, sparite, and bioclasts with subordinate intraclasts, ooids, Fe-oxides, and dolomites. Results of the physical properties show the rock has a mean PVU of 4859 m/s, a bulk dry specific gravity (Gsb) of 2.64, and very low water absorption capacity ranging from 0.2-5.7%, and Na2SO4 soundness ranging from 1-14%. UCS, AIV, ACV, and LAAV range from 20.5-180.5Mpa, 8-20%, 24-34%, and 18.9-31.1%, respectively. The physical, chemical and mechanical properties of the entire limestones sample comply with the required standards, suggesting their suitability as aggregate materials in road construction.To study the interrelationships between the physical, properties of the limestone aggregate, regression analysis was applied showing a significant interrelationship between these properties.

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Road construction requires a prime quality and a tremendous amount of aggregates, within which their quality is set by geological and geotechnical properties. Therefore, the Mesozoic limestone was studied in the vicinity of Harer and Dire Dawa towns, for the fundamental engineering assessments. Thirty-seven Mesozoic limestone samples obtained from the area were subjected to petrographic and geotechnical analyses to work out the suitability of the rock as a road aggregate. Physical properties were investigated using ultrasonic pulse velocity (UPV), water absorption, Na2So4 soundness, and specific gravity tests. However, the mechanical properties were determined using unconfined compressive strength (UCS), Aggregate crushing value (ACV), Aggregate Impact Value (AIV), and Los Angles Abrasion value (LAAV). The study aimed to see if the limestone aggregate complies with the globally accepted standards by employing geotechnical laboratory analyses and petrographic examination. The petrographic observations reveal the Mesozoic limestones of the area are dominantly composed of micrite, sparite, and bioclasts with subordinate intraclasts, ooids, Fe-oxides, and dolomites. Results of the physical properties show the rock has a mean UPV of 4859 m/s, a dry specific gravity of 2.64, and very low water absorption ranging from 0.2-5.7%, and Na2So4 soundness ranges from 1-14%. Among the mechanical properties, UCS, AIV, ACV, and LAAV range from 20.5-180.5Mpa, 8-20%, 24-34%, and 18.9-31.1%, respectively.Based on the aforementioned results, the limestones of the area are suitable for aggregate in road construction as they’re complying with ERA, AASHTO, ASTM, and BS standards used for pavement works.

The scarcity of lands for suitable quarry sites is rapidly becoming a critical growing problem in most developing countries of the world. Therefore, selection of optimal quarry sites for crushed aggregates is a prerequisite for safe operation and economic viability. The present study was carried out around Harer and Dire-Dawa towns located about 520 km from Addis Ababa. The main objective of the study was to identify optimal location of quarry sites for crushed aggregates by using integrated Analytic Hierarch Process (AHP) and GIS approach. Selection was carried out by considering factors such as lithology, land-use and land-cover, distance to built-up areas, distance to water bodies, distance to roads, relative relief, and slope angle. For each of the factors appropriate classifications and criteria were formulated based on its suitability. Finally, by utilizing all factors, weighted overlay analysis was applied to produce the quarry site suitability map. The resulted suitability map shows about 136km2 of the area is highly suitable, 1,587km2 is moderately suitable, and 2,166km2 has low suitability for quarry site development. The findings of the study will be helpful in narrowing down the area to the suitable areas that may further be studied through detailed field investigation. This result will also greatly serve as guide in quarry site selection in other states and/or other developing countries.

The problem of environmental degradation and pollution resulting from quarry operations is becoming a critical problem. Therefore, the selection of optimal quarry sites is a prerequisite for safe operation and economic viability. The present study was carried out around Harer and Dire-Dawa towns to identify the optimal location of quarry sites by using an integrated AHP and GIS approaches. The selection was carried out by considering environmental and socio-economic factors. For each of the factors, appropriate classifications and criteria were formulated. Finally, a weighted overlay analysis was applied to produce the preliminary quarry site suitability map. About 136 km2 of the area is highly suitable, 1,587 km2 is moderately suitable, and 2,166 km2 has low suitability for quarry site. The approach followed by the study helped to narrow the area to the suitable sites that may further be studied through detailed field investigation. Hence, it can be adopted elsewhere as a guide for economical quarry site selection.