A geopolymer mortar for wood and earth structures

In building construction, because of the hygroscopic nature of wood and earth brick and the low adhesion between these materials, cracks are formed at their interface when they are assembled. Geopolymer binder has been show to create strong bonds between wood and earth brick. Assemblies of wood and extruded earth brick with geopolymer binder were manufacture and tested. Double shear tests at two scales were carried out that provided evidence of good adhesion and information about the influence of the type of brick on shear behavior. The workability of the binder was improved by adding siliceous aggregates. The mortar obtained has an improved compressive strength, ranging from 3 to 8 MPa, depending on the aggregate size. FTIR measurements and thermal analysis were performed to determine the reaction mechanism.

► Possibility to use a geopolymer binder to make a stable assembly of wood and earth brick. ► Role played by the nature of the brick is determinant. ► The aggregates addition to geopolymer binder facilitates a mortar suitable for construction.