The Effect of Addition of Pozzolanic Tuff on Geopolymers

New geopolymerized materials are developed in Jordan using local materials and alkali solutions. The geopolymerization process is achieved by activating the raw kaolinite with alkaline sodium hydroxide solution. Silica sand is added as filler to improve the workability of the mixture. The new geopolymer was cured at temperatures under 80 °C for 24 hr.
The produced geopolymers proved to be highly durable under different physical and chemical conditions. The products gave a high unconfined compressive strength values higher than 45 MPa for dry conditions. Crystalline sodium aluminum silicate phases dominated mainly by Na-zeolites are responsible for the high compressive strength.
The effect of pozzolanic tuff on the physical and chemical properties of the geopolymers is investigated in this work. The preliminary results have indicated that the addition of 50% pozzolanic tuff gave the maximum compressive strength after 14 days curing time under dry and wet conditions (Fig. 1).
The high strength, heat resistance, low production cost, low energy consumption, and low CO2 emissions suit the use of the geopolymers as a green construction material.