Breakthrough in use of recycled, local materials in construction

Wadi gravel, available in various sand deposits in the southern region of Qatar, identified for use as aggregate

A research project has identified the main solid waste streams in Qatar for potential use in construction and investigated advanced technologies for recycling that could be effectively applied in the country. In a statement, the Ministry of Municipality and Environment (MME) said it was awarded the project by the Qatar National Research Fund (QNRF) regarding the implementation of recycled materials in construction.

 The three-year project began in 2018 and was led by Dr Mohamed bin Saif al-Kuwari from the MME; Dr Khaled Hassan, managing director of Infrastructure Research & Development (IRD) at the Qatar Science & Technology Park; Dr Ian Sims, international expert in geology – UK; Dr Murray Reid, expert in geo-technical and ground engineering - UK. It was implemented in partnership with the Public Works Authority (Ashghal).
 The project sought to explore the wider use of recycled and local materials in government projects in line with the Ashghal 'recycling roadmap' and the government strategy on sustainable development, the MME said in a statement.
 Wadi gravel is one of the main resources identified for use as aggregate in construction. A by-product from sand washing plants, it could provide high-quality aggregate provided appropriate processing procedures are applied. The project demonstrated that processing Wadi gravel using advanced crushing, screening and washing is essential to minimise gypsum deposits adhering 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 4.5mn tonnes alone.
 Advanced physical, chemical, mechanical and petrographic analysis was conducted on the processed Wadi gravel in specialised laboratories in the UK as well as the Ashghal research and development facilities.
 The results showed excellent performance and compliance with national and international specifications for use in concrete and drainage applications as a replacement for imported gabbro with positive impacts on cost and environment, the MME stressed.
 As part of the project implementation, the team worked closely with the Roads Department at Ashghal in using Wadi gravel as a pipe bedding material in trench soakaways, with an estimated 27 tonnes in an infrastructure project in Umm Slal.
 The monitoring of Wadi gravel after 18 months in service showed encouraging results for wider use in infrastructure projects.
 The project team also worked with experts and consultants from Ashghal on investigating the use of reclaimed asphalt pavement (RAP) in road construction.
 The technique is based on milling old roads and recycling RAP materials in new asphalt mixtures, with the 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 statement notes.
 The performance of RAP 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 and weather conditions.
 "The project team is delighted with the outcomes of the recycling implementation project that support Qatar National Vision 2030 and the Qatar Second National Development Strategy 2018-2022 on achieving environmental sustainability and optimising the use of local resources towards self-reliance," the MME said. "We would like to acknowledge the support received from HE Abdullah bin Abdulaziz bin Turki al-Subaie, Minister of Municipality & Environment; Sheikh Dr Faleh bin Nasser al-Thani, Assistant Undersecretary for Agriculture and Fisheries Affairs; and Dr Saad bin Ahmed al-Mohannadi, president of the Public Works Authority, for their continuous encouragement for innovation and development.
 "We are also grateful to QNRF for their funding and care to serve the country to achieve prosperity for the society."