Designing water resistant lightweight geopolymers produced from waste materials

In the present work, percentage of water absorption and pore structure of lightweight inorganic polymers (geopolymers) produced by fine fly ash, rice husk bark ash and palm oil clinker (POC) aggregates has been investigated. Different specimens, made from a mixture of waste materials, were subjected to permeability and porosimetry tests at 2, 7 and 28 days of curing. The specimens were oven cured for 36 h at 80 °C and then water cured at room temperature until 2, 7 and 28 days. The results showed that high amount of POC particles improve the percentage of water absorption at the early age of curing. In addition the ratio of “the percentage of water absorption” to “weight” of the POC-contained specimens at all ages of curing was much higher than that of POC-free specimens which make them suitable for lightweight applications. The total specific pore volume of the POC-contained specimens was smaller than POC-free specimens at early age of curing. Some empirical relationship was found to predict the total specific pore volume of the specimens by means of their percentage of water absorption at early age of curing with an acceptable approximation. The obtained results from Fourier transform infrared spectroscopy also confirm those results from permeability and porosimetry tests.