Usage of Wood Fly Ash in Stabilization of Unbound Pavement Layers and Soils

Modification and stabilization of road structure unbound layers has extensively been studied both at laboratory and field for decades. The most commonly used binders for soil modification and stabilization are cement and quicklime (CaO), but alternative pozzolans and their mixtures are of economical, technical and environmental interest. This study presents soil stabilization with wood fly ash (WFA) at laboratory. Natural sand (Sa), Sa mixtures with 10% and 20% WFA were compacted at optimal water content according to Standard Proctor test LVS EN 13286-2:2012, and California bearing ratio (CBR) tested according to LVS EN 13286-47:2012 for cured samples after 96 hours immersed in water with 2 kg surcharge and after 7 days sealed simultaneously. At the same time also Immediate bearing index was determined for natural soil and their mixture with 10% WFA. Results showed 3.79 times enhancement in CBR values Sa after 7 days curing, justifying that WFA is valuable material for hydraulically bound mixtures.