Development of Eco-Friendly Geopolymer Soil Stabilizers Using Waste Siding Cut Powder and Waste Glass

Abstract

Cement-based materials are widely used for soil stabilization, but their high CO₂ emissions during production pose environmental concerns. This study investigates an eco-friendly soil stabilizer using waste siding cut powder (SCP) combined with an alkali activator (AA), as a substitute for ground granulated blast furnace slag (BFS). We have conducted some laboratory tests using commercially available clay with 40% water content, focusing on unconfined compressive strength (UCS) and leaching characteristics of stabilized soil specimens. The soil stabilizers which were made from SCP alone required 200 kg/m³ of dosage to meet the UCS criterion for third-class construction-generated soil, while 150 kg/m³ sufficed with AA addition. Heat treatment of SCP at 110°C or 200°C further reduced the required dosage. Blending with ordinary Portland cement (OPC) or calcium hydroxide (10–20%) improved strength, achieving target UCS at 100 kg/m³ after 28 days. Arsenic leaching exceeding environmental standards was observed in some specimens, attributed to natural arsenic in the clay and minor contributions from AA derived from waste glass. Adding sufficient calcium hydroxide effectively reduced arsenic leaching through the formation of insoluble calcium arsenate. SEM-EDS analysis confirmed the formation of hydration and geopolymer-like products. These findings demonstrate the potential of using SCP in combination with AA and calcium-based additives for sustainable and effective soil stabilization.