Effect of treated palm fibers on the mechanical properties of compressed earth bricks stabilized by geopolymer binder based natural pozzolan

Abstract

Abstract The aim of this work is to study the influence of the palm fibers treated with soda hydroxide solution, on the properties of the compressed earth bricks stabilized with 15% of natural pozzolana based alkaline geopolymer binder. To achieve this objective, mortars composed of treated fibers at different levels (0.1, 0.2, 0.3, 0.4 and 0.5%) for a length of 4 and 16 cm, have been developed. These different mortars with those without fibers were subjected to mechanical (dry compression, wet compression, and flexion), physical (water absorption), mineralogical (XRD, FTIR) and microstructural (SEM/EDX) characterizations after 7 and 90 days. The results obtained show that, in general the addition of fibers improves the mechanical and physical properties of compressed earth bricks stabilized with 15% of alkali-geopolymer binder. In addition, the adding of treated palm fibers does not have an influence on the mineralogical composition of the composite bricks. The observation of the diffractograms of FTIR analysis shows that these fibers have a capacity to sorption water molecules. Furthermore, the optical analysis shows that the binder used perfectly encapsulates the fibers. This situation shows that the treated fibers act perfectly as a filler in the matrix. The maximum dry compressive strength and flexural strength values are obtained with the addition of 0.4% fibers at 90 days and are 8.08 and 5.8 MPa respectively. Furthermore, an additional of 0.4% of palm fibers in earth bricks stabilized by the alkaline geopolymer binder based natural pozzolan is recommended for the construction of buildings.