Evaluation and Optimization of the Engineering Properties of LDPE Fiber-Reinforced Sandcrete Blocks Using Taguchi Method

Sandcrete blocks are construction materials that are predominantly used in buildings in West Africa. Their constituents are similar to concrete with the exception of the coarse aggregates. Therefore, similar to the positive effect of fiber reinforcement in concrete, low-density polyethylene (LDPE) fibers are added to sandcrete blocks to improve their mechanical and water absorption properties. This study investigates the performance of sandcrete blocks reinforced with low-density polyethylene (LDPE) fibers obtained from wastewater sachets. While the reuse of LDPE in concrete has been explored, its application in sandcrete block production remains limited. This research addresses that gap by optimizing the effects of LDPE fiber content (0.33%, 0.67%, and 1%), fiber length (20 mm, 30 mm, and 40 mm), and water-cement ratio (w/c) (0.5,0.6, and 0.7) on key properties including density, compressive strength, flexural tensile strength, and water absorption. A Taguchi orthogonal array (L9) design was utilized to identify optimal mix combinations. Results showed that the mix with a 0.7 w/c ratio, 40 mm LDPE fiber length, and 0.33% fiber content achieved the optimum density. The highest compressive (4.02MPa) and flexural tensile (2.06MPa) strengths were obtained from a mix containing 0.67% LDPE fibers of 20 mm length and a w/c ratio of 0.6. The mix with the least water absorption also featured 0.67% fiber content, 20 mm fiber length, and a w/c ratio of 0.6. ANOVA results indicated that the w/c ratio was the most significant, contributing over 45 % to all measured properties. The findings support the development of sustainable, cost-effective sandcrete blocks suitable for non-load bearing applications. This study demonstrates the dual benefit of enhancing sandcrete block performance while addressing plastic waste management challenges, offering a sustainable pathway for future construction practices.