A new sustainable building block with similar properties to low strength concrete but made out of excavation waste material and vegetable oil has been launched.
The so-called Vegeblock has been jointly developed by research body TRL and Qatar’s Ministry of Municipalities and Environment to help increase construction sustainability in the Middle East.
The new material, also known as ”Smart Block”, is composed of recycled aggregates and used vegetable oil and is highly suitable for use as non-load bearing blocks said TRL.
The project was funded by the Qatar National Research Fund (QNRF) and has been developed from small scale samples produced in laboratories to full-size building blocks, using materials and techniques specifically suited to Qatari conditions and the Gulf region said TRL.
The research group said that the blocks are manufactured in a similar way to conventional concrete blocks, except that they are cured at a higher temperature for a longer period.
It said that by using recycled materials and avoiding the use of cement, production costs can be reduced and a carbon saving of up to 88% can be achieved compared to conventional concrete blocks.
To date, 400mm by 200mm by 200mm non-load bearing blocks have been produced. The team has also announced plans to take production of the material forward to full scale and release of a best practice guide for production.
Trial wall constructed
The aim of the project it said, was focused on the development of innovative precast blocks without the use of cement or primary aggregates. It said it expects VegeBlock to make a significant contribution to construction sustainability in Qatar.
TRL country director and head of Middle-East infrastructure Khaled Hassan said the launch of the VegeBlock was part of an ongoing collaboration with the Qatari government. The aim is to introduce new developments to improve sustainability and promote the adoption of green construction in Qatar and the rest of the region.
The components – used vegetable oil and waste excavation material – are mixed and compacted in a mould and cured in an oven at 170°C for up to two days.
The heat treatment oxidises and polymerises oil so it can act as a binder for the aggregate resulting in cured blocks with adequate strength and durability for use in construction.
Optimisation of the new material was carried out by testing different types of recycled aggregate and oils, oil content, compaction level, temperature and duration of curing in a series of laboratory tests.
TRL said that the laboratory trials demonstrated that a range of different types of waste material can be used, including unwashed sand, incinerated bottom ash (IBA) and excavation waste (limestone). Various types of used vegetable oils were also utilised including, palm oil, soybean oil and canola oil.
It said that durability tests indicated that VegeBlock was resistant to damage from water, salts and fuel.
A full size trial wall was constructed outdoors at the Qatar Standards offices in April 2016 next to conventional concrete block wall for comparison. TRL said that the condition of the wall had been monitored through the heat of summer and heavy rains in winter. It remained intact.