Making use of discarded PET bottles, a professor and four engineering students from the Lutheran University of Brazil (Ulbra) have created a ‘PET brick’ made out of quartz sand, cement and bottles.
‘The research appeared out of the necessity to clean the waters of the rivers [next to] Manaus city, in the Amazon, [which was] full of PET bottles, discarded by the population,’ explains physics professor Newton Silva de Lima. ‘Then I had the idea to confine the bottle of PET in a block of cement and sand, so that it could be used as a brick.’
To develop the material(pictured above), Lima and his team created a wooden mould 14cm by 39cm. A two litre PET bottle, sealed with air inside, was placed in the mould and covered by Portland cement and quartz sand. In compression tests conducted at the university, the brick was shown to withstand six megapascals (MPa), which is well within the resistance rate required by the Brazilian Association of Technical Norms.
‘The great advantage of the covered bottle of PET, confined inside of the brick, is that it possesses enormous resistance to compression. It keeps atmospheric air inside, [so it is also an] excellent thermal and acoustic insulator,’ says Lima. This property is particularly useful in the city of Manaus, where temperatures routinely reach 38ºC during the summer.
Lima strongly believes that the new brick offers several advantages – ‘It removes bottles from the rivers. It generates jobs and income for the population. It assures a better quality of life. It diminishes social inequalities. [And] the operational cost is low (anyone can make this brick).’
The success of this experiment has led Ulbra to offer a course that teaches masons how to set up electrical installation when using PET bricks. One architecture student at the university is constructing a model of a Brazilian house made with the brick, to inspire builders to use it.
Lima has also given lectures throughout the Amazon and other parts of Brazil to draw attention to this environmentally friendly and easy-to-create construction item. ‘I want to be able to benefit the population [who are] most deprived with this project,’ he says.