Compressed Stabilized Earth Block Shell Housing: Performance Considerations

Abstract

The adoption of structurally superior forms, such as domes and vaults, in combination with cheap, locally available materials is an efficient solution to low-cost housing. Earthen building materials, in particular, offer many benefits, such as sustainability, excellent climatic performance, low cost, and low carbon footprint. Furthermore, earthen masonry shells are typically designed as pure-compression structures, thus eliminating the need for expensive and energy-intensive materials, such as steel. However, although these shells are designed for compressive stress only, many show substantial cracking damage, which may become hugely problematic because these pathways enable water to enter and saturate the underlying material. This is concerning because moisture can severely compromise the strength and durability of earthen masonry. In this paper, the advantages and difficulties associated with adopting unreinforced compressed stabilized earth block (CSEB) masonry shells for low-cost housing are reviewed, particularly from a South African context. Of particular focus are issues with the performance (e.g., strength and durability) of these structures. Subsequently, considerations are presented to improve the longevity of CSEB shells, which are based on a review of the literature as well as an evaluation of several full-scale masonry shells built in South Africa. The case studies considered in this paper reveal that cracking may be detrimental to the performance of CSEB shell housing structures, particularly in low-cost settings where maintenance and repairs are often deficient.