Earth as Building Material – an overview of RILEM activities and recent Innovations in Geotechnics

TLDR

Earth construction dates back to 10 000 BC, remains popular worldwide, has evolved from adobe to rammed earth, yet lacks specific standards and many tests adapted from concrete ignore its water sensitivity. The paper reviews earth‑building techniques, recent innovations, normative aspects, and introduces deep‑soil mixing as a geotechnical method. RILEM established TC TCE in 2016, an international committee that defines testing procedures for earth‑based construction materials.

Abstract

This paper presents an overview of the different earth building techniques, the latest innovations and the normative aspects. The oldest man made earth constructions known to exist date back to 10 000 BC. Since then, earth has remained a popular building material throughout history. With time, different techniques evolved, starting from sundried adobe blocks to cob constructions, rammed earth walls and compressed earth bricks. Today these techniques are still being optimized and alternative binders, specifically adapted admixtures and surface treatments are being developed. Even though nearly one third of the world’s population lives in an earth construction, few specific building standards and testing methods exist. Many of the tests used today are based on tests for concrete and thus do not take into account the complex nature of earth constructions, such as their sensitivity to water. RILEM, the union of Laboratories and Experts in Construction Materials, Systems and Structures, set up a new Technical Committee in 2016: TC TCE (Testing and Characterisation of Earth-based building materials and elements). This committee, consisting of an international group of experts on the topic, aim to define testing procedures for earth as a building construction material. To end with, this paper also gives a short introduction to “Deep soil mixing”, an “earth” building technique dedicated to geotechnical engineering.