Assessing the Suitability of Using Pet Fiber and Binary Blended Binder for Enhancing the Performance of Earth Bricks

This study investigates the effect of incorporating PET (Polyethylene Terephthalate) fiber and
a binary blended binder in the production of stabilized earth bricks, assessing their suitability
as building materials. The research aims to evaluate the physical and chemical properties of
rice husk ash, analyze the mechanical properties of termite mould earth bricks, and examine
their thermal and microstructural characteristics. The methodology involved sourcing and
processing termite mould and rice husk ash, from Ede Osun state, and locally obtained plastic
bottles, which were shredded for incorporation. The sample were (100 x 100 x 50)and
( 200x100x50) for flexural test, sun dried. Various tests were conducted following ASTM and
BS standards, including compressive strength, water absorption and thermal conductivity. SEM
analysis was employed to assess microstructural properties. Results showed that compressive
strength varied with composition, where Sample D (45% TMS, 25% RHA) exhibited the highest
strength at 7 and 14 days (9.13 MPa and 9.47 MPa, respectively), while Sample A (60% TMS,
10% RHA) achieved the best long-term strength (11.07 MPa) at 28 days. Water absorption tests
indicated that lower RCA content resulted in better durability, while higher RHA content
increased porosity and reduced stability. SEM analysis highlighted that sample with higher
RHA and PET fibers formed a denser matrix with improved crack resistance, whereas sample
with a higher proportion of rice ash exhibited a weaker, porous structure. Flexural strength
results indicated that RHA content positively influenced compressive strength up to 10% but
negatively impacted flexural strength beyond that threshold, as excess RHA interfered with
binder hydration and weakened the material structure. The findings emphasize the importance
of optimizing the mix ratio to enhance strength while maintaining durability. This study
contributes to sustainable construction by promoting stabilized earth bricks with improved
mechanical and microstructural properties, offering a viable alternative to conventional
building materia