Title : Gum Arabic as a sustainable cement replacement for pavement foundation material stabilization
Abstract:
Reducing the environmental impact of road infrastructure requires developing construction materials that maintain adequate mechanical performance while reducing reliance on conventional cementitious binders. The study examines the use of gum Arabic (GA), a natural biopolymer, to partially or fully replace cement in a stabilized sand-clay composite intended for pavement foundation layers. A red clay soil (RCS) was stabilized by adding quarry dust (QD) at an optimized ratio of 40% RCS to 60% QD. The resulting composite was treated with 8% cement, progressively replacing it with GA at rates of 25%, 50%, 75%, and 100%. The materials were characterized using Modified Proctor tests, saturated and unsaturated California Bearing Ratio (CBR) tests, Unconfined Compressive Strength (UCS) and Indirect Tensile Strength (ITS) measurements and modulus of elasticity.
Regarding the mechanical characteristics, GA-containing mixtures maintain good tensile performance and develop compressive strength over time. After 28 days, the UCS reached 2.52 MPa for the mixture containing 2% cement and 6% GA (25% replacement), and 2.94 MPa for the mixture containing 8% GA (100% replacement). The formulation combining 4% cement and 4% GA (50% replacement) exhibited the highest ITS at 90 days (0.75 MPa) while maintaining a moderate modulus of elasticity, indicating a favourable balance between stiffness, strength, and deformability.
These results highlight the potential of locally available natural biopolymers to reduce cement usage in infrastructure.
