Experimental Studies of Flyash and Construction Waste based Stabilized Rammed Earth Block

Author Name(s): Vaishali J Rajurkar, Priyanka S Rewatkar
Author Email: rajurkarvj@rknec.edu

Abstract

Paper presents the study and check suitability of available local non swelling soil, as a rammed earth construction material. As per the previous study red lateritic soil deposits are considered to be the best material for rammed earth construction. Major deposit found in central India is black cotton soil which has high swelling and shrinking properly where as non availability of such lateritic soil. In this study the investigation of the local soil is used to develop rammed earth material and its suitability using industrial waste. Since rapid urbanization and innovations in technology generates huge amount of solid waste, which creates irreversible environmental harm. Construction Industry is one of the biggest industries which can reuse such waste as a construction material. Construction material like cement, steel, vitrified tile etc. required huge energy in their manufacturing also emits carbon. Soil and waste material from industries as a replacement of natural sand is used in study, which may require little financial investment. Nearly 50% reduction in embodied energy of buildings through use of low-energy consumption materials in conventional and alternative building systems.[4] The properties of cement and lime stabilized and un-stabilized rammed earth blocks were studied in terms of their wet and dry density, wet cube compressive strength, water absorption property etc. To restrict the density of blocks, all the test samples were prepared by dynamic compaction method using steel rammer and mould. The blocks were prepared by using available non-swelling red soil as base material which is blend with fly ash, construction waste and optimised mix was stabilized with various percentages of cement and lime as 8 and 4%. The test results show that, increase in the strength of the rammed earth blocks up to 25 % percentage of fly ash of total mix. Further increase in fly ash may reduce the strength, as the material become more heterogeneous. It is also reported that percentage of stabiliser and curing period increases the strength of blocks.

Introduction

Every day innovations in technological progress leads in industrialized products and in their optimisation, huge amount of waste is generated; however to meet the demand of raw material in production of new materials results in extraction of natural resources. Sand is one of the natural resource which has been restricted to used in construction industry, so the suitability of such granular material which can replace sand may study. Fast growing industrialization generates waste that is not being used, which cause irreversible environmental harm. Construction industry is the biggest industry which use large amount of material and manpower. The material required in such industry ex. cement, iron, aluminium and tile manufacturing consumes large energy, also the transportation of such products from large distance cause carbon emission. Another problem in hot aired region, like India, day by day increasing in temperature increases the operational cost of building. Solutions in such problems which reduces the environmental degradation and at the same time raw construction material is need not to transport from large distance, local soil and waste generated from surrounding industry can utilised in construction. The reuse of waste material from various industries is the another major concern, Fly ash is the waste generated from thermal power plants which is low density material, suspended particles of it in air may causes pollution also due to inadequate space their disposal cause hazardous effect over the surrounding atmosphere. Such material has a pozzolonic property which can be used as a replacement of cement. As per the ancient history earth constructions proves more energy efficient and thermally massive material than all other construction materials. Efforts are taken to develop sustainable material and construction technique which provides rational use of natural resources and can be used for low cost load bearing structure.

Conclusion

From the above study results the following conclusions are made: 1. The density of the CSEBs prepared is in the range of 18.6 to 21.1 kN/m3 and 18.3 to 20.8 kN/m3 when blended with cement and lime for 7 and 28 days. 2. The best results are obtained at 50% Construction waste and 25% Fly Ash with 8% cement and 4% lime by weight. Also it is observed that with the addition of 8% to 10% cement there is very marginal increased in strength value, so 8% of cement is suggested to use as a rammed earth material. 3. Higher unconfined compressive strength and stiffness is observed with increasing Fly ash content and the stress-strain curve changes from a ductile to a brittle behaviour. The nature of stress-strain curves is found to be similar for both 7 and 28 days of testing. The stiffness of CSEBs increases with strength. 4. Without utilization of stabilizer, the strength of CSEB obtained is very less or negligible. So, mixing of stabilizer with non-swelling red soil, fly ash and construction waste in CSEB is must. 5. The compressive strength of rammed earth brick is also observed that the strength is much better as compare to red brick, so used as a construction material. 6. The CSEBs prepared using lime and cement in proportions has clearly brought out the effectiveness of lime with cement in improving the long-term build-up of strength better than using cement alone. 7. The above material is suggested to the best alternative for load bearing wall or construction with rammed earth blocks for low cost and houses, local material is used for construction reduces embodied energy. 8. In hot aired region such material are observed to be thermally massive, reduces operational cost of building throughout its lifespan, also in such construction there is large potential for utilization of industrial and construction waste to be used as construction material for promoting sustainable construction.

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