22. Strength and Elastic Properties of Tank-Bed Soil and Lime–Pozzolana-Based Geopolymer Units and Prisms

The use of conventional cement is still unavoidable in the foreseeable future, and many efforts are being made, in order to reduce its use in building materials. These efforts include the utilization of supplementary cementing materials such as fly ash, silica fume, granulated blast furnace slag, rice husk ash, and metakaolin. Of late, geopolymer is emerging as a binding material which can be adopted for the production of precast products, and masonry unit is one such convenient product which can be produced. Geopolymers, also known as alkali activated products, can be made by using a variety of ingredients that are abundantly available locally. In the present study, combinations of geopolymer–lime, lime–pozzolana cement, tank-bed soil, and brick powder-based masonry units were made. Some of the favourable proportions, based on the compressive strength and water absorption, were considered to produce geopolymer bricks using ‘adobe’ approach. The modulus of elasticity of the masonry units ranged from 1800 to 6000 MPa, which is much higher than the modulus of similar strength, table-moulded bricks of South India. From among the 14 different types of units, 5 were chosen for evaluating the prism strength. The compressive strength of the stack-bonded prisms was found to be in the range of 1.8–5.5 MPa. This is also much higher than that of the prisms made using table-moulded bricks of South India, with cement mortar. It appears that geopolymer-based masonry has a potential to be used as load-bearing wall elements of low-rise structures.