Effect of the addition of brick kiln ash to clayey soil in unpaved roads

Abstract

ural roads serve as pivotal conduits for the transportation of harvested crops to distribution hubs in Guarapuava-PR, a national agricultural focal point. This study evaluated the impact of incorporating brick kilns ashes (BKA) into the lateritic soil of an unpaved roadway. Mixtures of soil and BKA with three distinct granulometries were formulated, featuring substitution rates of 25%, 50%, and 75% ash relative to the total mixture mass, characterized in terms of: particle size distribution, liquid limit (LL), plastic limit (PL), and the optimum point on the compaction curve under modified energy conditions (optimal moisture content and maximum dry bulk density). Results revealed that BKA inclusion led to increases in LL, PL, OMC, CBR, alongside a reduction of MDD and expansion for the majority of mixtures, particularly within granulometry C1 at a 25% content. Finer ashes exhibited prominence in ISC and expansion outcomes. Substitutions of 75% BKA detrimentally affected geotechnical properties; however, granulometric stabilization with BKA proved feasible, particularly in soil-C2 mixtures designated for use as a sub-base. These mixtures met recommended LL and PL parameters, providing effective waste mitigation and presenting an alternative for soil improvement in pavement applications.