DETERIORATION OF CONCRETE INCORPORATING RICE HUSK ASH WITHOUT PROCESSING UNDER SIMULATED ACID RAIN ENVIRONMENT
Cement production was expressed as the second largest contributor of CO2. Therefore nowadays, creature of environmentally friendly concrete is increased so that economy development does not have to stop for the sake of the environment. The acidity of rainfall in the majority of Indonesia has a pH value ranging from 3 to 5. This condition indicates that rainfalls at several cities were acid and would damage the concrete. The aim of this study is to use rice husk ash as a cement substitute in concrete mix in order to reduce damage caused by acid rain attack. This study is an experimental study using rice husk ash, as waste material from the burning husks in brick produce. Before using the ash in mixing, it was filtered with #100 sieve. It also examined its characteristics using scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD). Specimens were cubes while to simulate acid rain; acid solution mixing H2SO4 and HNO3 was used in this study with two pH values. The independent variables in this study consist of the rice husk ash percentage and pH values. Rice husk ash replacement levels of 0%, 5% and 10%, by weight of cement were used in this experiment. Immersion of specimens takes until 90 days. The experiment used two levels of pH which were 3 and 4. Furthermore, the dependent variable is the deterioration of concrete. Deterioration was measured by three parameters, namely compressive strength, CaO/SiO2 ratio and percentage of SO3. The data was collected by conducting a SEM test and compressive strength test on the specimen. The results of this study showed that rice husk ash could potentially be used as a cement substitute in the concrete to decrease the deterioration of concrete due to acid rain.