Carbon Conscious Construction: Evaluating Compressed Stabilized Earth Blocks

The United Nations Environmental Programme and the Paris agreement emphasize the urgent need for net-zero embodied carbon in building materials by 2050. In line with the vision, this study investigates the production and performance of compressed cement-stabilized earth blocks (CSEBs) as sustainable alternative for wall construction. Soil samples from Kara, East of Addis Ababa, were analyzed for their suitability in block production, focusing on grading, plasticity, and chemical composition. Using Portland pozzolana cement (PPC) as a stabilizer, blocks were produced with varying cement contents and compaction pressure and tested for compressive strength and compaction pressure. Results show that blocks with as little as 6% cement content achieved compressive strengths exceeding 2 MPa at 56-day curing, meeting structural requirements. Higher cement content and compaction pressure further improved compressive strength and reduced water absorption. Importantly, the study demonstrates that CSEBs can reduce cement consumption by over 50% compared to conventional hollow concrete blocks, translating to significant embodied carbon savings, up to 2 tonnes of CO2 per 100 m2 of wall. These findings highlight the potential of CSEBs to contribute meaningfully to climate mitigation, while offering technically viable and resource-efficient solutions for sustainable and affordable construction.