English abstract
The construction of residential projects has the largest portion of construction industry in Oman. In this study, compacted blocks made of sand dunes and clay (Attapulgite), with some stabilizers like Ordinary Portland Cement (OPC) or Cement Kiln Dust (CKD), were fabricated for low-cost housing. The blocks were manufactured using a manual Cinva-Ram press machine. The sand and Attapulgite characterization tests were performed to verify the suitability of these materials for producing suitable blocks for construction. The effects of OPC and CKD on compressive strength, and density have been studied. The total water absorption, surface water absorption, and thermal conductivity of the produced blocks were scrutinized to select the best blocks.
Five different proportions (series) of sand and Attapulgite stabilized with OPC were studied. Each series contained 8 mixes with percentages of cement as 5, 6, 7, 8, 9, 10, 12, and 14% of the total volume of the mix. Similarly, three series of dune sand and Attapulgite were mixed using 5, 6, 7, 8, 9, 10, 12, and 14% percentages of CKD. At least three blocks were made from each of the 64 mixes ((5+3)8 = 64). The mixes were numbered using abbreviation to represent the materials, the series number, and the % of the stabilizer, i.e. SAC1-05 means Sand, Attapulgite, Cement, and Series 1with 5% of cement, and SAKD1-05 means Sand, Attapulgite, Kiln Dust, Series 1 and 5% of CKD. The result showed that the 64 mixes tested, SAC2-13 and SAC2-14 were found to give the highest compressive strength of 7.8N/mm2 at 28 days after casting. The SAC2-13 mix was selected for further tests of density, total water absorption, surface water absorption and thermal conductivity. The density of compressed blocks using normal soil according to (ARS 680, 1996) ranges between 1800 – 2000 kg/m3. The produced dune sand blocks had lower average density, due to the fact that dune blocks cannot be compressed to reach similar densities. The block consider it has good total water absorption and thermal conductivity where surface water absorption consider considered a bit high.
