Challenges, opportunities, and solutions in low-cost building envelopes: A case study of low-strength masonry systems

In addition to addressing the basic need of shelter, building envelopes must address concerns of load transfer, energy efficiency, durability, and resilience with respect to natural and human-produced disasters, among other structural and aesthetic concerns. This paper discusses the key barriers to the use of low-tech compressed earth blocks in a resilient and sustainable manner. The paper also presents a process improvement approach through which low-tech masonry approaches can be used to provide a context-appropriate, cost-effective resilient solution. Typical compressive strength values of masonry can range from 7 MPa to 20 MPa for commonly used concrete masonry units (CMU). Compressed earthen masonry usually peaks at somewhere between 3 and 5 MPa. When working with these lower numbers, general concerns arise from masonry being an elastic-brittle material and become more significant. This paper adopts a process improvement approach to propose a stabilization strategy that can be used to enhance the quality of blocks produced. Fibers are included in the blocks in this research to address susceptibility to local failure when the masonry is exposed to impact load from, for example, flying debris in a high wind region. The process improvement approach is used to optimize the use of fiber in compressed earth blocks and also explore the feasibility of using a low-strength, soil-cement mortar to achieve strength compatibility with the optimized blocks.