Enhancing sustainability of rural adobe houses of hills by addition of vernacular fiber reinforcement

Adobe is a commonly used building material in rural houses of district Hamirpur of the North Indian state of Himachal Pradesh. Adobe is a sustainable material but has limitations of building smaller room sizes and requires frequent maintenance which is not suitable for modern lifestyle. These become main reasons for rejection of adobe as a building material. Initial investigation comprising of water content analysis, specific gravity analysis, grain size analysis, plastic limit and liquid limit analysis, maximum dry density check reveals that soil is sand clay and its low compressive strength shall be increased for enhancing its sustainability. For this purpose, stabilization with natural fibers of Pinus roxburghii and Grewia optiva in 0.5%, 1%, 1.5% and 2% proportions is proposed. Total 360 cubical and cylindrical shaped samples of both stabilized and unstabilized compositions were prepared and tested in a laboratory according to Indian standards. Unconfined compressive strength tests and maximum Stress Carrying Capacity tests were conducted after 07 days, 14 days, 28 days, 56 days and 90 days of casting. Results reveal that compressive strength of soil increases by 131–145% with addition of fiber P. roxburghii and 225–235% with addition of fiber G. optiva for cubical and cylindrical samples respectively. Increased compressive strength also results in a reduced thickness of traditional mud walls thereby increasing internal room size which would suit to changed modern lifestyle requirements. Enhanced properties of adobe will result in wider acceptance of adobe as a building material that will make development of rural housing more sustainable on a wider scale.