Testing the use of volcanic tuff in base and sub-base pavement construction in Jordan

This article investigates engineering properties of base and sub-base materials for pavement construction in Jordan, and the possible improvements on their engineering properties using volcanic tuff (VT) to avoid bad performance and frequent maintenance in highway pavements. Current study examined the use of VT that was found in Al-Hala-Mountain in Tafila in Southern Jordan, in order to be used in pavement construction. Pure base and sub-base materials and mixed materials at 10-80% ratios of VT were tested for their engineering properties. Results showed a noticeable improvement was experienced in engineering properties. Addition of 40-60% of VT to materials was noticed to improve strength and compaction of materials, soundness and resistance to abrasion and weathering, improve size gradation, decrease absorption of water and penetration to soil base that expected to decrease swelling and build up pressure in soil base, and increase permeability of water in layers. Current study recommends to use VT in pavement construction in Jordan, and to conduct further tests and practices in order to include specifications of VT in Jordanian Standards for pavement construction. VT use in pavement will improve performance and lower cost of construction and maintenance, and avoid the industrial waste through mining, transportation and construction.