This research aims to develop the concrete blocks mixed with cassava pit waste. There are 6 mixing ratios among Portland cement type1: rice hush ash: quarry dust: cassava pit waste: water reducer type A: tap water that include 0.7: 0.3: 10: 0: 0.02: 0.6 0.7: 0.3: 9.9: 0.1: 0.02: 0.6 0.7: 0.3: 9.7: 0.3: 0.02: 0.6 0.7: 0.3: 9.4: 0.6: 0.02: 0.6 0.7: 0.3: 9.1: 0.9: 0.02: 0.6 and 0.7: 0.3: 8.8: 1.2: 0.02: 0.6 by weight. The concrete block samples were casted same as the ordinary concrete blocks and test were conducted according to TIS.57-1990 standard. From the results the best proportion of concrete block mixed with coconut shell ash is 0.7: 0.3: 9.7: 0.3: 0.02: 0.6. The proper ratios of cassava pit waste can decrease the density or weight and increase the thermal insulation of concrete blocks. However the over amounts of cassava pit waste that effected to increase the water absorption and decrease the compressive strength properties of concrete blocks.

This research aims to study the using cassava pit wastes mixed with cement to particle board walls. The Portland cement type1: fine sand: tap water ratio is equal to 1: 0.5: 0.416 by weight. The ratios of cassava pit wastes to cement are used following: 0.05 0.06 0.07 0.08 0.09 and 0.10 by weight. The cassava pit wastes are crushed by plastic plastics granulators (pass sieve no.4). The casting of particle board walls use the compression machine in room temperature (30 – 35 degree of Celsius) and control 0.75 g/cm3 of density. The TIS 878-2537 standard (cement bonded particle board: high density) is followed to test the properties of particle board wall. Resulting the cassava pit wastes mixed with cement can cast to particle board walls and have good properties especially the thermal insulation property.