Alker Buildings
 | Alker History  | Alker Technology

February 14, 1997
Southern California Institute of Architecture 

Assoc. Professor
Istanbul Technical University
Istanbul - TURKIYE



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




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

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



Water Content  Workability
18-29% rammed earth 
20-22% adobe blocks 
24% and more segregation


To obtain required strength and durability

Traditional earth 
ALKER construction
15-21 days strengthing 20 min. strengthing
curing area no curing area
water sprinkling no water sprinkling
rain protection no rain protection



ALKER  technique decreases a number of processes

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.