For a year and a half in Kazakhstan, scientists have experimented with making up and testing samples of composite material for the construction of the road foundations. They mixed up a local loam with industrial waste from the Karaganda Iron and Steel Plant. To these two components, they added waste from lime production to activating the chemical interaction of metal slag and loam through the leaching reaction.
Because of that reaction between the particles of the mixture, a constantly compacting gel formed, which eventually gets a stone-like state. The composite showed very high water and frost resistance and low expansion/contraction parameters at temperature fluctuations.
"Due to the new composite, the construction of road foundations supposed to be faster and more cost-effective because of replacing a large amount of relatively expensive sand and gravel with waste from local metallurgical production and loam. That one and similar technologies are not only cost-effective but also help to solve the problem of recycling environmentally hazardous industrial waste. A similar composite is suitable for road foundations construction in different countries. The main thing is to determine the materials at the initial stage of road design", said Andrey Taskin of FEFU School of Engineering.
The author of the idea of the development, Vsevolod Mymrin, professor at the Federal University of Technology - Paraná/Brazil (UTFPR), explained that when in the composite compound, heavy metals became part of new formations where they are chemically bonded at the atomic level. That makes them wholly safe for the environment. The composite considered environmentally friendly and meets strict safety standards.
Mr. Mymrin went on that the application of the new composite should prolong a no repair road life span about two times since over time the composite becomes approximately 1.5-2 times stronger compared to the initially projected durability of the foundation of the road. The testing of the new composite is still ongoing.
Thanks to its mechanical properties, the new composite is suitable not only for the production of road foundations but also for the manufacturing of such building materials as unfired bricks, blocks and similar components which would be also environmentally friendly and cost-effective.
The waste from the iron and steel industry is one of the most significant environmental pollutants in the world. The annual global production of pig iron smelting slag is about 400 million tons.
Recently Engineers from the Military Studies Center at Far Eastern Federal University (MSC FEFU) developed a brand-new concrete with improved impact endurance and up to 40% made of waste such as rice husk cinder, limestone crushing waste, and siliceous sand.
This work was supported by the Ministry of Higher Education and Science of the Russian Federation (No. 10.3706.2017 / 4.6) and the Ministry of Education and Science of the Republic of Kazakhstan (Project No. 149 of March 14, 2018).