title: Development of Unfired Brick Through Alkali Activation Using Waste from Aggregate Recycling Facility as an Alternative to Conventional Fired Clay Brick
Creators: name: Shubbar, A
Publisher: name: Liverpool John Moores University
Year: 2023

description: Bricks have been playing a significant role in building and construction for thousands of years for their outstanding properties such as good durability, strength and low costs. In the UK, fired clay bricks are one of the main elements needed to fuel the construction industry in the country with annual production of more than 2 billion bricks. However, the production of fired clay bricks is energy intensive and considered one of the main producers of carbon dioxide (CO2). Therefore, searching for alternative techniques in the production of bricks is becoming essential in order to develop environmentally friendly bricks to replace fired clay bricks and reduce their negative environmental impact. One of the alternative techniques in the production of bricks is the alkali activation technique (geopolymerisation) that depends on the poly-condensation of the raw materials normally containing silica and alumina in the presence of an alkali solution to produce amorphous to semi-crystalline geopolymer. This technique is very attractive relative to firing of brick as the final products can provide structural strength in a very short time, they are sufficiently durable and CO2 emissions are reduced significantly. This research reports the development of a Novel Alkali-Activated Unfired Brick (NAAUB) using clay filter cake (CFC) waste produced during the washing of recycled construction and demolition materials. Comparisons of strength (compressive strength), durability (water absorption and freeze and thaw cycle effect), thermal properties (thermal conductivity) and CO2 emissions during the manufacturing and operational processes of the NAAUB and the conventional fired clay brick have been carried out. The results indicated that the NAAUB showed comparable compressive strength (25.8 MPa) relative to conventional fired brick (25.7 MPa) after 7 days of water curing. Regarding the limited durability properties studied of the NAAUB, the results indicated that the water absorption rate of the NAAUB was very low and was significantly lower than that of the conventional fired brick. Additionally, the results of the freezing and thawing cycles showed that the NAAUB has no physical damage after 180 cycles of freezing and thawing and it can be classified as a frost resistant brick. Furthermore, the results of thermal properties of the NAAUB indicated good thermal behaviour that will help in increasing indoor comfort and reducing the overall consumption of energy required for heating/cooling of any structure that is using this brick relative to conventional fired bricks. The results of the CO2 emissions indicated that replacing the conventional fired brick with the NAAUB could reduce the CO2 emissions by about 51.4% and 5.65% during the manufacturing process and operational process, respectively. The comparison between the cost of the NAAUB and conventional fired brick indicated that the NAAUB is cheaper than the conventional fired brick by about 5%. The overall results indicated that the NAAUB is a successful alternative to conventional fired bricks in different applications with the benefits of decreasing the CO2 emissions and decreasing the overall cost of bricks. .