Identification of Durability Problems in Earth Buildings

Abstract

Sri Lankan house construction in ancient times was dominated by earth construction. However in the past few decades, earth construction has been overtaken by burnt bricks and cement blocks in the housing industry. However, stabilized earth was reintroduced to Sri Lanka with the development of sustainable construction concepts and due to high cost of brick and block masonry construction. The stabilized earth construction includes Compressed Stabilized Earth Blocks (CSEB) and rammed earth construction. In order to popularize these technologies, the strength and durability of such materials have to be comparable with the brickwork and cement block work. A number of past studies conducted have determined the strength properties of both the stabilized earth masonry which have been proven as equally good as the conventional materials. In order to assess durability of earth buildings a detailed field study was conducted to investigate the problems associated with the existing earth structures. These field studies included ancient houses and recently built houses with stabilized and un-stabilized earth, with parameters like wall thickness, plinth level, wall spans and heights, etc. This study provides very useful information to quantify and access the levels of durability problems with different earth bricks, blocks and walls. This paper presents the outcome of a detailed study conducted by investigating the durability problems of existing earth buildings and also the testing methods to assess the durability of different earth walls. The outcome of this research will be very useful to improve the durability of earth buildings.

Long Term Existence of Cement Stabilized Rammed Earth Walls

“…The experimental programme on durability properties of earth buildings indicated that cement content above 5% may be able to almost eliminate durability related problems. It further revealed that laterite soil available in Sri Lanka could give durable and strong walls with at least 5% cement for stabilization [9]. The basic control factors for satisfactory achievement in cement stabilization are selection of good soil, adequate cement content, proper moisture content and adequate compaction.…”

“…The composition of 5-20% gravel, 45-60% sand, 20-35% silt and clay has been recommended for better performance of wall construction. Composition can be checked by performing a jar test [9]. Careful selection of the earthen materials for a CSRE wall is required consistently to maintain the required minimum strength and each soil mix must be analyzed and tested to determine the appropriate amount of cement required to meet the minimum strength specified [10].…”

Earth Construction Durability: In-Service Deterioration of Compressed and Stabilized Earth Block (CSEB) Housing in Algeria

“…The returns are generally based on a review or reported after a large building degradation or collapse. For instance, the document elaborated by Arandara and Jayasinghe (2007) on the durability of the CSEB construction gives prominent insight. The project focused on the report of the degradations observed on a group of 50 houses, 59 % of which were built in Matara (Sri Lanka) with stabilized earth blocks.…”