ASSESSMENT OF THE COMPARATIVE EFFECTS OF FACTORY-MOLDED AND MANUALLYMOLDED BLOCKS ON BUILDING PERFORMANCE IN INDUSTRIALLY POLLUTED AREAS: A CASE STUDY OF PORT HARCOURT

Sandcrete blocks are the most widely used walling units in Nigeria, yet their quality varies depending on whether they are factory-molded or manually-molded. In industrially polluted areas, where emissions from refineries, cement factories, and manufacturing plants accelerate material degradation, block performance becomes critical. This study assesses the comparative effects of factory-molded and manually-molded blocks on building strength and durability under polluted environmental conditions. Results show that factory-molded blocks consistently achieve higher compressive strength, dimensional accuracy, and resistance to environmental stressors compared to manually-molded blocks. Manually-molded blocks, though cheaper, often fail to meet Nigerian Industrial Standards (NIS 87:2000), leading to reduced service life and higher maintenance costs. The findings highlight the need for stricter quality control, improved block manufacturing practices, and environmental adaptation strategies in Nigeria’s industrial zones.