Clay fired bricks are commonly encountered in the construction sector as infill between structural frames. This system has been favoured by builders due to familiarity, ease of manufacture, and they also do not require skilled labourers to erect. Produced from moulded clay and hardened by firing in a kiln, brick production is both energy intensive and high in CO2 emission. Fired bricks are typically held together by cement mortar at the bed and perpend joints which provide very minimal resistance against shearing or flexure. This meant brick walls often require additional wind posts or stiffeners to provide stability. Compressed earth masonry offers an alternative to the conventional brick walling system in that, besides having the advantages of conventional bricks, they also confer higher compressive strengths due to the high-pressure compaction manufacturing process. The high strength allows the system to be adapted into load-bearing masonry system for use in low-rise buildings as an alternative to the more expensive reinforced concrete or steel framing system. The high-pressure compaction process along with high quality moulds also give fair-faced finished to the bricks, allowing them to be used as facing bricks and eliminating the need for surface finishing such as plastering. Additionally, compressed bricks featuring interlocking key holes along the bed joints allows for simplified and faster wall erection process. This review paper aims to document the research progress thus far in adopting the compressed interlocking bricks as a sustainable alternative to current building materials.

No abstract

Spent bleaching earth ash (SBEA) is harmful waste from the oil refining industry that has previously exhibited pozzolanic properties and potential for use as cement replacement. Conventional pozzolanic replacements in cements are typically limited to 30 % only as excessive amounts have detrimental on cement strength. This research aimed to investigate the feasibility of increasing the level of replacement past 30 % through mechanical activation. Preliminary investigations revealed that SBEA contains sufficient silica and alumina oxides to be classified as Class N pozzolan in accordance with ASTM C618. As expected with pozzolans, the use of SBEA in cement mortar improved the 28 and 56-day compressive strengths up to 30 % substitution but at the same time also increased the water requirement. Mechanical activation was able to improve the level of substitution to 50 % through a mix of increasing pozzolanic reactivity of SBEA as well as increasing the specific surface area of its particles.