A. Situation before theinitiative began
All over the world, earthconstruction has mainly been developed around the technology of CEB, which ismostly stabilised with cement. To our knowledge, nowhere in the world hasresearch & development been conducted for using stabilised earth infoundations or waterproofing and, in India, for rammed earth walls.
B. Establishment ofpriorities
The priorities arose from thedifferent stages of the construction site. This building was the result ofyears of research and development and it became the opportunity to develop andperfect further what was achieved before. In fact the main priority was to getstabilised earth plasters for waterproofing the roof.
These priorities involved only thestaff of AVBC/ Earth Unit: From the project holder to the workers.
C. Formulation of objectivesand strategies
The main objective was todemonstrate that this building could be built entirely with stabilised earth.Subsequently, it was to implement all the research and development done by AVBC/ Earth Unit. The second objective was to get waterproof earth plasters for thevaults.
The general strategy wasto build this building step by step, while developing further what was achievedbefore. Its implementation depended on the availability of funds. The secondstrategy was in two steps:
1. Experiments in the laboratory of various mixes.
2. Implementation at real scale with new proportions.
The project holder established theseobjectives and strategies.
D. Mobilisation of resources
As mentioned earlier, thisinitiative was born from years of research and development in the use ofstabilised earth in every part of a building. Human resources have always been,from the very onset, the main origin for all this R&D. At the head of thisR&D was the project holder and he mobilised workers, masons, supervisorsand technicians from the surrounding villages, who could implement his ideas.
The main technical resource camefrom the background of the project holder, as an architect postgraduate inearth architecture and construction.
The financial resources for theimplementation of the initiative have been the most difficult to mobilise! Funds were received after long and laboriousfund raising. They came from different sources:
1. Grants from HUDCO
2. Individual donations
3. Funds generated by AVBC / Earth Unit on other projects
E. Process
The implementation of theinitiative mainly faced a problem of funds. This is the main reason why it tookfive years to build this Training Centre. This problem was overcome by thefaith in what had to be done and by a persistent endeavour to raise funds.
HUDCO, which is agovernmental organisation, always supported the initiative in spirit. But itsfinancial support was difficult to obtain! Only at the end of last year itcould contribute financially to complete the initiative.
On the technical sidethere were no really problems, and therefore no problems remain to be solved.
Results achieved
All objectives haveentirely been achieved: the Training Centre implemented stabilised earth fromfoundations to waterproofing:
|
FOUNDATIONS |
· Stabilised rammed earth with 5 % cement. |
|
BASEMENT |
· CEB with 5 % cement. |
|
PLINTH BEAM |
· Composite plinth beam with CEB – 5 % cement. |
|
INSIDE FLOORING |
· CEB tiles, 2.5cm thick, with 5 % cement. |
|
FLOORING OF THE
OPEN COURTYARD |
· Stabilised earth concrete with cement and a lime-alum paste. |
|
PAINTS & PLASTERS |
· Various stabilised earth plasters.
· Earth paints stabilised with white cement. |
|
WALLS |
· Stabilised rammed earth with 5 % cement and a “homeopathic milk of lime and alum. |
|
LINTELS AND BEAMS
|
· Composite ones (single, double or triple height): with CEB – 5% cement, and RCC. |
|
COLUMNS |
· Composite pillar with CEB – 5% cement, and RCC. |
|
ROOFS
|
· Various vaults built “free spanning” (without centring), with CEB stabilised with 5 % cement. |
WATERPROOFING
|
· Earth-sand plasters stabilised with various percentage of cement, lime-alum paste and the juice of a local seed. |
The best achievement isthe efficiency of the stabilised earth waterproofing:
An exceptional rain (23rdto 27th February 2000) gave over five days 402 mm of rainfall. Thevaults had no leakage and no dampness inside! This comparative survey was measured with an electronichygrometer:
|
MOISTURE |
After 402mm rainfall in 5 days |
2 weeks after rainfall, under sun |
|
Outside |
Inside |
Outside |
Inside |
Vault |
100 % |
31. 6 % |
19. 4% |
22 % |
|
Window sill |
59. 8 % |
27. 8 % |
20 % |
21. 8% |
Some works were verydelicate and the quality and consciousness of the workmanship evolvedtremendously during this construction site.
F. Sustainability
The sustainability is expressedmainly through environmental aspects and, to a lesser extent, cultural ones.
1. Environmental: The production ofstabilised earth consumes much less energy and emits much less pollution thanfired earth. A survey from Development Alternative – New Delhi 1998 – shows:
|
PER M2 OF WALL |
Kiln fired bricks |
Country fired bricks |
CEB |
Rammed earth |
|
Energy consumption |
539 MJ / m² |
1657 MJ / m² |
110 MJ / m² |
110 MJ / m² |
|
Pollution emission (CO²) |
39 Kg / m² |
126 Kg / m² |
16 kg / m² |
16 Kg / m² |
Therefore, CEB and rammed earth present these advantages tofired earth:
|
Energy consumption |
Pollution emission |
|
2.4 times less than kiln fired bricks.
7.8 times less than country fired bricks. |
5 times less than kiln fired bricks.
15 times less than country fired bricks. |
The technologies involved changedthe construction patterns in the area quite a lot:
- They are more labour intensive, and especially with moresemi-skilled labour.
- They upgraded the skill of all labour and gave a newknowledge to masons, with the construction of vaults and all related works.
The earth used for building thetraining centre was partly taken from the biological wastewater treatment pond.This parameter is an essential one for the management of resources.
The Training Centre uses abiological wastewater treatment by “Lagonning system” for the grey water only.
2. Cultural: A sensible change ofattitude and behaviour of the workers has been noted over the years. Thelabour, from simple worker to mason and supervisor, has become much moreresponsible and conscious of quality and efficiency parameters. From thefeeling they were just paid workers they have now become conscious that manualwork can be fulfilling and valorising.
G. Lesson learned
The main lesson, whichwas learned over the years, was that stabilised earth could be used in manyparts of a building: from foundations to roof. Therefore it was entirelyintegrated in the initiative, as in fact it was its essence.
The exercise of buildingthis Training Centre was a lesson in itself, which laid the base for a newunderstanding of soil stabilisation and the project to develop further thisresearch.
Therefore, the strategiesand plans of action are now to implement all the knowledge acquired in everyforthcoming project.
H. Transferability
The technologies, whichwere implemented in the initiative, have been transferred since 1992 tohundreds of artisans, students and architect/engineers. It is happening throughour regular training course on production of CEB, rammed earth for foundationsand walls, arches, vaults and domes, and all particular details related withthe CEB masonry.
These trainees weremainly from India but alsofrom various countries (France,Germany, Holland,Senegal, Sri Lanka, Tibet,UK and USA).
The next step for thetransfer of technology will be for stabilised earth waterproofing. The resultsachieved in this field with the red soil of Auroville are entirelysatisfactory. They could already be disseminated to the entire East Coast ofIndia, which has more or less the same pedological formation. But more researchshould now be undertaken with other types of soil. Only then, could thisknowledge be transferred all over the world.
