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Alker Buildings | Alker History | Alker Technology
GYPSUM ADOBE CONSTRUCTION TECHNOLOGY
February 14, 1997
Southern California Institute of Architecture
BILGE IŞIK, Ph.D...,
Assoc. Professor
Istanbul Technical University
Istanbul - TURKIYE
OUTLINE
- Purpose
- The Soil
- Proportionning of Gypsum + Lime Adobe (ALKER)
- Properties of ALKER
- Workability
- Curing
- Construction
- Labor
Purpose
Earthen construction is vulnerable to moisture and can be easily damaged
by earthquake. However, indoor quality in earthen construction is very
healthy. It provides protection against hot and cold weather conditions, in
view of its high thermal capacity and insulating values. Because of these
advantages, earthen construction technology is subject to research in both
in the industrialized and unindustrialized countries.
In this research, gypsum and lime are mixed to the soil to promote the
properties of the material. The gypsum stabilized soil sets in a short time,
which makes the production time shorter and the curing unnecessary. It also
makes the production period independent from the rainy days. The material is
porous, thereby increases the insulting value.
The mechanized construction technology for the gypsum stabilized earthen
construction aims to improve the local construction material for
mass-housing. It will also contribute to preserve the natural sources and
save funds for the country.
The Soil
To obtain required strength and durability
| Traditional Earthen Construction |
ALKER construction |
| preprocessing |
preprocessing is not necessary |
| grinding |
____________
|
| sieving |
____________
|
| setting the soil aside |
____________
|
| 30% clay |
10% clay |
Proportion of ALKER(Gypsum
+ Lime Adobe)
| Ingredient |
% by Weight |
Practical Measures |
| Soil |
100 |
2 full wheel barrow |
| Gypsum |
10 |
4 shovel full |
| Lime |
2 |
1 shovel full |
| Water |
18-20 |
1 bucket full |
General Properties
- improves the water absorption property
- improves the mechanical properties
- improvers the heat insulation
- low shrinkage
- clean surface
- short setting
- short construction time
Physical Properties
| Unit weight |
1.6-1.7 kg/lt |
| Shrinkage |
1.0-1.5% |
| Compressive strength |
2.0-4.0 N/mm2 |
| Shear strength |
0.9-1.3 N/mm2 |
| Water absorbtion |
very low |
Long term water exposure
(except direct rainfall) |
no erosion |
| Heat transfer value l |
0.4-0.5 kcal/mhC |
| Specific calorific |
1.0 kJ/kgK |
Workability
| Water Content |
Workability |
| 18-29% |
rammed earth |
| 20-22% |
adobe blocks |
| 24% and more |
segregation |
Curing
To obtain required strength and durability
Traditional earth
construction |
ALKER construction |
| 15-21 days strengthing |
20 min. strengthing |
| curing area |
no curing area |
| water sprinkling |
no water sprinkling |
| rain protection |
no rain protection |
Construction
- The gypsum stabilization enables a shorter construction time
- The external walls are 45cm tick, this provides thermal property
- The load bearing internal walls are 30cm
- Wall oppennings are 25%
- Foundations and tie beams are reinforced concrete
Labor
ALKER technique decreases a number of processes
- 4 laborers can erect 2.5-4.5 m3 of walls/day
- 100 m2 house has approximately 45 m3 walls, therefor, 4 laborers can
complete a hose in 10 days
Production Method of Gypsum Adobe (ALKER)
Material :
Earth:___________100 kg__________100%
without humus
clay (appr. %10) + silt + sand + grvel (7 cm)
Water:____________20 kg__________20%
Gypsum:___________10 kg__________10%
Lime:______________2 kg___________2%
Mixing : mechanical mixer (or shovel)
Process :
| mixer + earth + 2 kg water |
2 minutes mechanical mixing |
| barrow + water 18 kg + lime 2 kg + gypsum 10 kg |
2 minutes hand mixing |
pour the barrow full of mixture into the mixer
(water 18 kg + lime 2 kg + gypsum 10 kg) |
3 minutes mixing |
| pour the mixture to the wheel borrow; ramm it into the wall form |
in no longer than 15 minutes |
Please inform Bilge ISIK about the
results with your full address and a short CV.
Your interest is appreciated.
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