Lightweight Geopolymer Binder Base on Sidoarjo Mud

Sidoarjo mud has been a disaster for society and government of Indonesia, but this material contains of SiO2, Al2O3 and Fe2O3 so that significantly to be expected as a potential pozzolanic material. It would be very useful to take the advantages of the material. Moreover, lightweight concrete is widely applied especially at high-rise buildings in order to reduce the risk of earthquake. In general lightweight concrete is made with less Portland Cement associated with lime and pozzolanic materials as a binder. In this paper, calcined-Sidoarjo mud was introduced as pozzolanic material to create geopolymer paste. Geopolymer binders were made with a mixture of calcined-Sidoarjo mud, fly ash and alkaline activator. The specimens were then mixed with a commercial chemical foamed agent to get lightweight geopolymer binders. The results showed that the mixing with the ratio of fly ash : NaOH: Na2SiO3 were 33,3% : 33,3% : 9,52 % : 23,81% and superplasticizer was 2,5% of binder weight achieved the compressive strength of 55,6 MPa. With additional 1% of foaming agent, the compressive strength of lightweight geopolymer binder was 7.1 MPa