Compressive Strength Performance of Cement-Treated Base (Class A) with Waste Paper Pulp as Partial Fine Aggregate Replacement

Abstract

The growing demand for sustainable road infrastructure has encouraged the use of alternative materials to reduce dependence on non-renewable natural resources. This study aims to evaluate the effect of waste paper pulp as a partial replacement for fine aggregate on the compressive strength of Cement-Treated Base (CTB) Class A and to determine an optimal and economical substitution level that meets technical requirements. An experimental program was conducted using Portland Pozzolan Cement (PCC), fine and coarse aggregates, and waste paper pulp as a fine aggregate substitute at replacement levels of 0%, 30%, 40%, 50%, 60%, and 70% by volume. Two mixture conditions were examined: mixtures without superplasticizer and mixtures containing 0.3% superplasticizer by weight of cement. Cylindrical specimens measuring 150 mm in diameter and 300 mm in height were prepared using a standard layered compaction method and cured under moist conditions. Compressive strength tests were performed after seven days of curing. The results show that compressive strength decreases as the proportion of waste paper pulp increases for both mixture conditions. A compressive strength of 48.12 kg/cm² was achieved at a 30% substitution level without superplasticizer, satisfying the CTB Class A requirement of 45–55 kg/cm². Although the addition of superplasticizer enhanced compressive strength, the 30% waste paper pulp mixture without superplasticizer was identified as the most economical and suitable composition. The findings indicate that waste paper pulp can be effectively utilized as a sustainable fine aggregate replacement in CTB Class A applications when applied at an optimal proportion.