The Engineering Study on the Use of Crushed Stone Aggregate and Crusher Dust Mixes in Flexible Pavements of Karachi-Hyderabad Motorway, Sindh, Pakistan

The development of the country is directly related with the better road communication from mega cities to rural villages. Pakistan is a developing country and has started a grand network of highways, superhighways and motorways in all four provinces along with Kashmir and Northern and northwestern regions bordering china and Afghanistan. Highway Flexible pavements are the most commonly used form of pavements and have four component layers namely Sub-grade, Sub-base and base and surface courses, which are constructed of materials like natural soils, sand, morrum etc., are considered to be costly in terms of construction as well as maintenance. The result of plastic fine sand their sticky characteristics in natural soils hampered the performance of the pavement. To reduce the impact of failures alternative materials are to be investigated. In this connection an attempt is made by using Crushed Stone Aggregate and Crusher Dust as road component materials. Gradation mixes were prepared to meet the specifications of National Highway Authority Pakistan and subjected for various geo-technical characterizations such as gradation, compaction, strength etc. According to the results of strength values of compacted crusher dust and Crushed Stone mixes have been evaluated through a series of CBR tests by varying the crusher dust and sand contents from 10% to 60%. On the other hand, the suitability of compacted crusher dust as a road base and sub-base materials have been verified in accordance with N H A P specifications and findings that 20-30% in place of sand can satisfy the materials used as sub-base and base courses [1-3]. Keywords: Pavement; Highway; Void ratio; CBR; Construction