TRL, a global centre for innovation in transport and mobility, and Qatar's Ministry of Municipalities and Environment (MME), have announced the launch of ‘VegeBlock’, a new innovative building block designed to help increase sustainability across the country's construction segment.

The product was launched at a special seminar held at the Ministry of Municipality and Environment Tower.

Present during the launch were Dr Mohammad bin Saif Al Kuwari, head of the Environmental and Municipal Studies Institute (MME), and Dr Khaled Hassan, country director and head of Middle East Infrastructure, TRL, along with key stakeholders in the construction industry.

The launch of VegeBlock, also described as ‘Smart Block’, represents the latest stage in an ongoing programme of collaborative work between MME and TRL to improve the sustainability and adoption of green construction in Qatar and the rest of the region. Previous projects have focused on the use of locally available recycled and secondary aggregates in place of imported primary aggregate, said a statement.

The project was funded by the Qatar National Research Fund (QNRF) at the Qatar Foundation, National Priorities Research Programme (NPRP 6-1472-2-600). During the event, attendees were briefed on how VegeBlock 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. The properties of VegeBlock were described, including the announced plans to take their production forward to full scale and the release of a Best Practice Guide for its reproduction.

VegeBlock is composed entirely of recycled aggregates and used vegetable oil, and is manufactured in a similar way to conventional concrete blocks, except that they are cured at higher temperatures for longer periods. The product has similar properties to low-strength concrete and is suitable for use as non-load bearing blocks in buildings. By using recycled materials and avoiding the use of cement, the cost of production and the carbon footprint of VegeBlock are significantly lower than that of conventional concrete blocks being used today, the statement said.

VegeBlock is produced from excavation waste material (limestone) and used vegetable oil. The components are mixed and compacted in a mould and cured in an oven at 170 deg C for up to two days. The heat treatment results in oxidation and polymerisation of the oil to act as a binder for the aggregate resulting in cured blocks with adequate strength and durability for use as construction blocks. These innovative blocks have strength and durability properties similar to non-load bearing concrete blocks (M4 & M6 in the Qatar Construction Specifications QCS 2014) but do not require the use of cement, water or imported aggregates, it said.

A series of laboratory testing programmes were carried out to optimise the process and determine which materials to take forward for the full-size production of VegeBlock. The optimisation process included different types of recycled aggregates and oils, oil content, compaction level, temperature and duration of curing.

The laboratory trials demonstrated the diversity of using various types of waste material, 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. For each combination of aggregate and vegetable oil, the optimum oil content was established and the optimum compaction level, curing temperature and curing duration determined. It was found that the optimised mixtures produced VegeBlock — meeting and complying with Qatar Construction Specification (QCS 2014) requirements for compressive strength and water absorption for non-load bearing concrete blocks. Durability tests indicated that VegeBlock was resistant to damage from water, salts and fuel.

Full-scale production trials were then carried out at the Khalid Cement Industries factory in the Industrial Area in Doha. The aggregate used was limestone derived from excavation waste, screened to be finer than 8 mm. Used vegetable oil was selected as the binder, thus using only recycled materials as well as avoiding the use of cement and imported aggregate. The production was carried out using the same facilities available for producing conventional concrete blocks in Doha. The process resulted in the production of large sized blocks (400 x 200 x 200 mm) that met the Qatar construction specification requirements for non-load bearing blocks.

A trial wall of full-size VegeBlocks was constructed outdoors at the Qatar Standards offices in April 2016 with a wall of conventional concrete blocks for comparison. The condition of the wall has been monitored through the heat of summer and heavy rains in winter. To date, it is still intact after 10 months in service. Monitoring and testing of the trial wall will continue to provide more confidence in use, the statement said.

VegeBlock offers various advantages as compared to conventional blocks including the use of locally-available waste and recycled materials and avoiding imports. VegeBlock also provides environmental benefits in terms of reduced emissions of carbon dioxide compared to conventional concrete blocks.

A preliminary economic analysis indicated that the production costs (materials plus operational costs) for VegeBlock could be significantly lower than concrete blocks. The material and operational cost for manufacturing is estimated to be two thirds the cost of conventional concrete blocks. However, there is a need to develop a bespoke system for full-scale production of VegeBlock, which may impact on the capital cost. A more detailed economic analysis should be carried out when a specific plant is under consideration, it said. – TradeArabia News Service