Modeling of Brick Properties for Earth-Based Domes Structures

Abstract

The use of earth-based materials is becoming increasingly popular, particularly in the rural areas of developing countries. One example is the introduction of an earth dome for low-cost housing in the rural areas of Mozambique [1], although this project is still at a research level. The earth bricks used in building the dome are a type of composite material, consisting of porous soil and possibly cement. The brick properties depend on the proportions of soil, cement and air-filled pores. For economic reasons, the amount of the stiffer and stronger cement phase needs to be minimized. Here, some initial experimental results and the results of a simple numerical model for estimating the stiffness and strength of the bricks are presented. The numerical analyses use a 3D linear elastic finite element program to calculate the effective elastic properties of the brick and a failure stress under uniaxial compression is calculated based on a Drucker-Prager type condition for cohesive materials.

Keywords:

• Construction materials
• Elasticity
• Finite elements
• Soil-cement composites
• Stiffness
• Strength

ACKNOWLEDGMENTS

We are grateful for the support received from the U.S./Africa International Materials Institute at Princeton University, funded by the National Science Foundation, and from Brown University without which this work would not have been possible. S. J. Magaia is also grateful to C. Bull of Brown University for his assistance in carrying out experiments there.