Stabilization of compressed earth blocks (CEB) by pozzolana based phosphate geopolymer binder: Physico-mechanical and microstructural investigations

Abstract

This work proposes the poly(phospho-ferro-siloxo) binder resulting from the phosphoric acid activation of pozzolana (PZ) as a friendly stabilizing agent for compressed earth bricks (CEBs). Different proportions of pozzolana were incorporated into the clay soil (5, 10, 15 and 20 wt%). The CEBs were cured at 25 °C and at 70 °C. Powder X-ray diffraction (PXRD), Fourier transformed infrared spectroscopy (FTIR), water absorption as well as mechanical strength tests were used to characterize the 28 days aged CEBs. The compressive strength of CEBs varies from 9.2 to 20.6 MPa and 10.2 to 42.8 MPa at 25 °C and 70 °C, respectively. Water absorption ranges from 6 to 11% at 25 °C and 8 to 12% at 70 °C. These results indicated the possibility to use pozzolana based phosphate geopolymer binder as efficient stabilizer for the development of structural and functional CEBs. Pozzolana based phosphate geopolymer binder appears as energy-efficient and sustainable solution for the stabilization of CEB.