By Aminaton Marto, Mohammed Ali Al-Bared and Zahiraniza Mustaffa
With the circular economy agenda promulgated worldwide to reduce waste and carbon footprint, our built environment sector needs to reduce, reuse and recycle materials. For example, for soil stabilisation, instead of using virgin materials, we can use recycled tiles and tyres; in the production of new material such as the engineered concrete, we can substitute cement or aggregate with shredded tyres or powdered tiles.
If the question is about quality, contrary to commonly-held beliefs, recycled materials are actually not secondary and, in some cases, they even improve the engineering properties. Research shows, for example, that soft soils modified using these materials can withstand heavy loads and become more suitable for construction.
Soft soils have low shear strength and engineering properties that do not meet design requirements, as well as exhibit excessive settlement when loaded. Thus, their poor physical characteristics are not suitable for foundation or any construction applications. Marine clay and peat are two types of soft soils, and some clays and peat exhibit expansive properties—swelling when gaining water and shrinking when drying out.
Aminaton Marto, PhD, is currently a visiting professor at the Disaster Preparedness and Prevention Centre of Malaysia-Japan International Institute of Technology, Universiti Teknologi Malaysia. Her specialisations are in soft soil engineering, geotechnical investigation, geotechnical earthquake engineering, disaster mitigation and forensic engineering. She pioneered research on bamboo-geotextile composite, as well as coal ash for soft soil improvements and other applications.
Mohammed Ali Al-Bared, PhD, is a post-doctoral research scientist at the Department of Civil and Environmental Engineering, Universiti Teknologi Petronas, Malaysia. He has extensive research experience and published numerous articles in journals and international conferences in the areas of civil engineering, geotechnical and geological engineering. He is currently working on soft soil improvement techniques in terms of dynamic and static loading effect.
Zahiraniza Mustaffa, PhD, is an associate professor at the Department of Civil and Environmental Engineering, Universiti Teknologi Petronas for more than 15 years. Her specialisation is in the field of pipeline engineering, hydraulic engineering, urban hydraulics and probabilistic structural designs. She is currently an Honorary Secretary of the women engineers’ section of the Institute of Engineers (IEM), Malaysia; as well as a Chartered Engineer of the Engineering Council, UK, and graduate member of Board of Engineer Malaysia (BEM).