Today Bangalore boasts of housing nearly 10,000 homes with stabilised mud blocks. That makes the city score over other cities in the country in terms of its impressive numbers. But the effort to get there with professionals working towards the acceptance of the material, and propagate the science involved in using the earthy material have been Herculean. In the late 1980s there were media reports that spoke high of a young engineer who had all the nerve in him to take up ‘mud as a material’ for construction of his own home. Hudco too had joined hands in the new revolution to bring in more awareness and finance them in easier ways. The young engineer referred to in the media was M.R. Yogananda, a doctorate in Civil Engineering from IISc. What has it taken for engineers and research scientists to get this far?
Dr. Yogananda, Founder of Mrinmayee, a stabilised soil-block consultancy firm, says, “With the city also being home to a striking number of architects, it’s time we thought of mud as a medium for construction. Irrespective of the cement costs, one has to think about ways to reduce material consumption in construction, as most consume high energy in production and transportation. Yogananda, propagating sustainable methodologies in construction, says, “In the long run, it is not just cement that matters, but concrete where aggregates and sand are involved.”
Dr. Yogananda and his firm have even used the stabilised mud blocks at Kutch where earthquake-resistant features were introduced in the buildings by way of “horizontal RC bands along with vertical reinforcements.”
In Soil Stabilised Blocks we are looking at utilising mud excavated at the site itself, without transportation involved, he explains. “Stabilised Mud Blocks came into the picture when energy consumed to burn bricks had to be saved. Soil Stabilised Blocks are a mixture of majorly mud (72 to 75 per cent) with small portions of cement (7 per cent), sand and lime depending on the location-specific mud. The silt-mud of Delhi will have to bring coarse-aggregates into the mix, the sandy soil of Kanakapura would eliminate the necessity to blend sand, while acidic mud would have to get in lime water too. These blocks have the potential to be mixed with any industry/factory generated waste.” From the time that Yogananda built his house with mud-blocks when people with apprehension said, “it will just collapse, wait for the rain,” these three decades have seen the mud-researcher take up hundreds of projects to squash unscientific myths and guide people into considering the natural material along with a big team of professionals working towards a larger social cause. “The test for my house was the first rain when satisfied onlookers walked in for enquiring the costs,” he says.
Dr. Yogananda spoke to The Hindu-Property Plus about several aspects of the mud blocks that need to be understood before one decides on using them for construction…
Excerpts…
Your association with mud blocks is nearly three decades old. What finally led you towards Mrinmayee?
I was involved in the R & D work on alternative building technologies at ASTRA (now CST) and the Dept. of Civil Engineering, IISc., headed by Prof. K.S. Jagadish in addition to pursuing Master’s and Ph.D in the same field. The main thrust was to reduce the embodied energy in buildings. ASTRA was a front runner in this research. Stabilised mud block technology for walls and alternatives for RC roofs were developed during this period.
When there was the opportunity to build my own house in 1987-88, I decided to do it with stabilised mud blocks. Hudco took the initiative to propagate this technology then, calling it a ‘mini mud revolution in Bangalore’. In a way, my house provided confidence to people who wanted to explore cost-effective and earthy alternatives. I started helping people who wanted to use stabilised mud blocks and this led to the starting of ‘Mrinmayee’ a soil testing lab and consultancy on mud blocks, in addition to training artisans and contractors.
In the current scenario, would you recommend mud blocks as they are into the category of being an earthy material, for social consciousness, or for saving money?
SMBs can be used for load bearing construction without reinforced concrete columns and beams by adjusting the stabilising percentage depending on the number of storeys and roof spans for a particular building, thus reducing the consumption of steel and concrete. The buildings constructed using SMBs can be exposed without plastering and this cuts down on the consumption of cement and sand. This helps conserving high energy materials like steel and cement and a scarce expensive material like sand without sacrificing the structural stability of the building. I would reiterate that it also enhances the aesthetics, looking earthy.
The break-up of the cost must be looked into in terms of how much goes for the material and how much for labour. If we look into the future, we have to look at reducing the material consumption in buildings as resources are finite. The alternatives in terms of using SMBs in buildings can reduce the overall wall cost by about 15 to 20% as compared to burnt brick walls.
Investing in good quality exposed block work is a step in the right direction to revive the artisan skills that are important in the building construction.
Why did people take so long to realise the potential of stabilised mud blocks when the cost factors were also not alarming? Is there an inherent risk in getting a homogenous quality of mud blocks, or is there a dearth of people for advice? Are architects and contractors also to be trained for propagation?
Training architects, engineers, masons and semi-skilled personnel in these alternative methods of construction by regularly conducting hands-on workshops is a very important step towards implementing these ideas in the field. Mrinmayee and Gramavidya (an NGO) in Bengaluru have been playing this role for more than two decades.
It is necessary to understand the process properly with good supervision for producing good quality SMBs as is the case with any good product. There has been an increase in the number of users of SMBs in buildings spread all over India in the recent past. Information dissemination and proper training will take this forward.
What are the unique ways in which mud blocks are used in a construction even for an interesting interior décor?
Special purpose interlocking blocks, pigmented blocks, cornice blocks etc., can also be made with stabilised mud. SMBs can be effectively used for constructing arches. Filler-slab roofs with SMBs as filler material in the tension zone can be a very effective alternative for conventional RC slabs.
Masonry vaults and domes are good options for roofing leading to better thermal comfort. They can be built without the regular formwork/centering. Such roofs require much less steel as compared to RC slabs. Several buildings have been constructed using SMBs with these special features leading to cost effectiveness.
(Mrinmayee conducts one-day hands-on workshops for using soil stabilised blocks where every kind of advice can be solicited. Contact 080-26582970 / mrinmayee8819@gmail.com / gramavidya@gmail.com)
