The Ministry of Environment and Climate Change (MoECC) has announced the launch of a book titled 'Implementation of Recycled Aggregate in Construction' at a special ceremony held as part of the ongoing Doha International Book Fair (DIBF).
The launch took place in the number of ministry officials and members of the public.
Dr Mohamed bin Saif al-Kuwari, who led a research initiative that sought to explore the wider use of recycled and local materials in government projects, highlighted different aspects of the book.
"The use of recycled aggregate in Qatar and the Gulf region is relatively new, and can make significant contribution to the vast infrastructure development witnessed over the last decade. Lack of experience with recycled aggregates in the aggressive conditions of the Gulf, particularly lack of long-term performance data, has raised concerns on the durability and long-term performance of
recycled aggregate in service, as compared to primary aggregates," the ministry said in a statement.
"The purpose of the book is to support the government's strategy of sustainable development through the effective implementation of recycled aggregates in construction," it stressed. "Qatar National Vision 2030 reinforces sustainable development and places great emphasis on preserving and protecting the environment, as one of the four pillars of national development, alongside social, economic and human development. With the vast investment made in infrastructure projects, the government has set targets for the efficient use of natural resources, with a recycling target to use 20% of recycled aggregate to replace primary aggregate in government construction projects by 2022."
Government initiatives for facilitating the implementation of recycling include the development of relevant standards and specifications, guidelines and manuals that permit the use of recycled aggregate in various construction applications, and a consistent supply of recycled aggregates at regulated prices.
The approach adopted in the book is to use practical evidence, based on site data in real exposure conditions up to five years in service, for the performance assessment of recycled aggregates. Recycled and alternative aggregates were used to replace primary aggregate in different proportions in various construction applications of asphalt, concrete and unbound granular products. The assessment was done on the basis that the construction products made with recycled and alternative aggregate should produce a performance that is at least equivalent to that of conventional construction products made with primary aggregate.
Recommendations are made for the wider and more efficient implementation of recycled aggregate in construction.
The book sheds light on the main solid waste streams in Qatar with advanced technologies in innovative construction products. Wadi gravel is one of the main resources identified for use as aggregate in concrete and unbound applications.
The material is produced as a by-product from sand washing plants. Wadi gravel is processed using advanced crushing, screening and washing to minimise gypsum deposits adhering to the particles to acceptable levels for use in construction. Wadi gravel is available in
various sand deposits in the southern region of Qatar, mainly the areas of Al Kharaij, Al Kharara and Mekaines, with the latter deposit containing approximately 4.5 million tonnes alone.
Advanced testing of physical, chemical, mechanical and petrographic analyses was conducted on processed Wadi gravel in specialised
laboratories in the UK and the Public Works Authority (Ashghal) Research & Development Centre within the Ashghal Quality and Safety Department.
The results showed excellent performance and compliance with national and international specifications for use in concrete and drainage applications as a replacement to imported gabbro with positive impacts on cost andthe environment.
As part of the project implementation, the team worked closely with experts from Ashghal in implementing Wadi gravel as a pipe bedding material in trench soakaways, in one of the infrastructure projects in Umm Salal. Monitoring th performance of Wadi gravel after 18 months in service showed encouraging results for wider use in infrastructure projects.
The use of reclaimed asphalt pavement (RAP) in road construction was also investigated. The technique is based on milling old roads and recycling the RAP materials in new asphalt mixtures, with conservative use of gabbro and bitumen.
RAP recycling has positive impacts on cost and the environment, with the potential use of 100% materials to improve aggregate supply chain and accelerate project completion. The performance of RAP asphalt was monitored in five Ashghal projects in the Doha, Al Wakra, Old Airport and Izghawa areas, with positive and encouraging results after exposure to traffic loadings and weather conditions.
The project team is delighted with the outcomes of the recycling implementation project that support the Qatar National Environment and Climate Change Strategy.
A research project was awarded by the Qatar National Research Fund (QNRF) to the then Ministry of Municipality and Environment on the use of recycled materials in construction. The three-year project commenced in 2018 and was led by Dr al-Kuwari along with other experts. It was implemented in partnership with Ashghal.
The statement acknowledged the support received from HE Sheikh Dr Faleh bin Nasser al-Thani, Minister of Environment and Climate
Change; HE Dr Abdullah bin Abdulaziz bin Turki Al-Subaiei, Minister of Municipality; and Dr Saad bin Ahmed al-Muhannadi, president of Ashghal, for their continuous encouragement of innovation and development, while also thanking QNRF for its funding and sponsorship of the scientific research project that serves the country and achieves prosperity for the community.