Performance of Granular Volcanic Ash for Use as Pavement Materials under Various Conditions

Abstract

Granular volcanic ash (GVA) is found in large amounts in many regions of Yemen. Because this material has poor qualities, like being very light, and having many holes, it can't be used as a base for roads. This dissertation aims to evaluate the performance of GVA materials for construction of road in Yemen under two conditions. First condition (Stabilization Condition) two types of GVA materials with different color (referred to as red and black GVA) are mixing with fine soil (0%, 10%, 20%, and 30% of the dry weight of GVA) and stabilized by cement (2%, 5%, and 8% relative to GVA dry weight) besides curried the GVA-cement –fine soil samples for 7 and 28 days to use as pavement materials for low to medium traffic roads. In this condition the performance of GVA-cement–fine soil mixture by different criteria including compaction performance, strength performance, durability performance and the ultrasonic pulse velocity (UPV) performance. Tests results showed the GVA with 20% fine soil and 5% cement content fulfilled the strength and durability criteria of pavement construction with low to medium traffic. Second condition (Replacement Condition) partially replaced base coarse aggregate (basalt aggregate) by the two types of GVA ( 0%, 10%, 20%, 30%, 40% and 50%, of total weight of dry aggregate) to use for construction of roads with heavy traffic. The performance of the base coarse materials –GVA mixture in this condition was evaluated by compaction performance, strength performance, and abrasion performance. Tests and results showed the maximum GVA content for base coarse materials -GVA mixture to use as base coarse materials fulfill the two criteria (CBR and Abrasion) is 20%.