The Role of Building Materials and Architecture in Achieving Sustainable Housing in the Global South : A Case Study from Tanzania

Sammanfattning

This thesis analyzes how sandcrete blocks used in housing construction in Tanzania can be optimized in terms of cost-effectiveness and reduced climate impact, without compromising structural performance. The study is based on a methodological approach using the Sustainability Opportunity Study, integrating field studies, interviews, and experimental analysis through Design of Experiments. The results indicate that the current use of cement is largely inefficient and relies heavily on empirical assessments rather than standardized measurements. To evaluate the effect of composition, four mix designs (Mix 1-4) were tested with varying water and cement contents. The study shows that Mix 2 (10 % water and 5,5 % cement) achieved the highest compressive strength of 3,8 N/mm2, while Mix 1 (10 % water and 4 % cement) reached 2,8 N/mm2, which is close to the Tanzanian standard's minimum requirement of 3,0 N/mm2. By adjusting the mixing proportions, such as using coarser sand and precise control of water and cement content, that the cement content can be optimized without falling below strength requirements. This proposed optimization yields significant economic and environmental benefits, demonstrating that manufacturing costs can be reduced by up to 35 percent and carbon dioxide emissions significantly decreased.