Recycled Construction Materials for Sustainability

Recycled Construction Materials for Sustainability

By Mr. Prabhan Sak Raksaiwan

Managing Director

LWSS Wisdom and Solutions Co., Ltd.

How is everyone doing these days?

Following the 8.2 magnitude earthquake from the Sagaing Fault in the Republic of the Union of Myanmar on March 28, 2025, the tremors affected many areas in Thailand, particularly in Bangkok and nearby provinces. This event caused damage to buildings and infrastructure, as well as loss of life and injuries among the public. I hope everyone has recovered from the shock and returned to work and life as usual. I firmly believe that this incident has prompted many of us to question the causes of such natural disasters and discuss how we can adapt our business practices to mitigate environmental impacts that may negatively affect our world, including the sustainability of businesses, society, and the planet.

When it comes to sustainable real estate development, you likely think of environmentally friendly design and construction, as well as waste management for recycling and reuse. According to statistics from the Pollution Control Department and economic data from relevant agencies, the volume and value of recycled waste have been increasing annually, from approximately 8.8 million tons valued at around 117 billion baht in 2022 to 9.31 million tons valued at around 124 billion baht in 2023. It is expected that the volume of recycled waste will grow to no less than 10 million tons, valued at around 150 billion baht in 2025.

Did you know that besides the familiar recycled materials we often see, such as recycled plastic bottles (rPET Bottle), recycled paper, recycled plastic bags, recycled clothing and shoes, and recycled furniture, there are also recycled materials used in construction? These include recycled steel, recycled concrete, recycled wood, recycled bricks, recycled insulation, recycled flooring/walls, and recycled decorative tiles/glass. Particularly, recycled steel and recycled concrete are increasingly used at affordable prices.

Currently, the production of steel and concrete worldwide, including in Thailand, not only involves high-quality steel from the smelting process and cement but also incorporates a variety of materials, especially environmentally friendly recycled materials through standardized production processes to meet the demands of environmentally friendly construction.

In Thailand, technology for recycling steel is being utilized, particularly through the use of Induction Furnace (IF), which melts steel using electrical induction to generate heat until the metal melts, resulting in low raw material loss. However, it cannot remove impurities from the molten steel, and while it can melt steel quickly, it has limitations regarding the purity of the raw materials, which can be expensive and hard to find. The Electric Arc Furnace (EF) is a modern steel melting technology that uses an electric arc furnace to melt steel, recognized globally for its ability to purify steel by removing impurities. This is considered an environmentally friendly furnace since the raw material used for melting is solely recycled steel, resulting in lower pollution and energy consumption during melting.

Both production processes can produce steel that meets the standards for steel in Thailand, which are covered by industrial product standards (TIS) set by the Industrial Product Standards Office (TIS). For example, TIS 20-2559 (reinforcing steel bars for concrete), TIS 24-2559 (deformed reinforcing steel bars for concrete), and other standards related to various types of steel. These standards define quality, strength, chemical properties, usability, material quality, and testing methods. In Thailand, steel containing approximately 20% to 100% recycled steel, depending on the type of steel, does not affect the quality or strength according to product standards.

Comparison Table of Steel Melting Methods

Regarding concrete, in Thailand, the mixture includes cement, water, stones, and sand, with the addition of fly ash, a material produced from burning coal, used to replace a portion of cement at levels of approximately 15-30% to improve properties and reduce environmental impact. However, the mixing of fly ash must be in appropriate proportions, and the quality of the fly ash must meet standards to ensure it does not affect the quality and strength of the concrete, in accordance with established standards. Additionally, there is hydraulic cement according to industrial product standards TIS 2594, which can replace Portland cement, providing a smooth concrete surface, resistance to abrasion and spalling, high compressive strength suitable for various structural works, and reducing greenhouse gas emissions.

Comparison Table of Properties Between Hydraulic Cement and Portland Cement

From the production standards of both steel and concrete mentioned, these materials are standard for constructing all types of buildings in Thailand today. The recent "earthquake" has empirically proven that the materials used in construction in Thailand meet usage standards, even with the inclusion of recycled materials.

Therefore, the strength of the structure does not solely depend on the composition of steel and concrete that uses recycled materials in its production, but rather on the selection of materials with engineering properties that meet standards and align with design standards. Thus, choosing recycled materials for construction that meet engineering and architectural standards not only ensures the strength of the constructed buildings but also contributes to a circular economy and is environmentally friendly, making it a truly sustainable business for us and the world.