Process Materiality Analysis: Concrete Pavers Segment
The Value Chain for the Concrete Pavers Segment
The most important steps in the value chain for the concrete pavers segment described in the following apply to the Semmelrock business unit.
Sustainability in the supply chain and in raw material sourcing
Concrete pavers consist primarily of sand, grit, gravel and cement; the essential raw materials for cement production are limestone and clay and/or marl. The main focus in the extraction of these mineral raw materials is on the safety and health of employees, the protection of local residents against noise and dust pollution, the protection of the natural environment and the re-use of depleted extraction sites. The production of cement is a highly energy-intensive process requiring firing temperatures of about 1,450 °C. High-calorific fuels, such as coal and fuel oil, are used to reach such high temperatures. To a growing extent, however, these are being replaced by other fuels of fossil origin, such as used tires, processed plastic materials and waste oil. Over the entire life cycle, from raw material extraction to end-of-life disposal, cement production accounts for a major part of the CO2 emissions caused by Semmelrock’s concrete products. The use of recycled concrete helps to minimize the carbon footprint and, at the same time, diminishes the burden on extraction sites.
The fact that heavy-weight aggregates, such as sand, grit and gravel, are transported only over short distances helps to minimize transport-related CO2 emissions. Therefore, the availability of sufficient extraction sites in the vicinity of production plants is essential.
Environmental aspects in production
Compared with other processes within the Wienerberger Group, concrete paver production consumes relatively little energy. In the process of drying concrete products, thermal energy is even released and can be recovered. The use of renewable sources of energy helps to reduce direct CO2 emissions. Raw material efficiency can be increased through the avoidance of breakage and scrap and the re-introduction of production waste into the production process. Intelligent product design results in raw material savings and, at the same time, maintains a high level of product quality. Water, an important raw material for cement-bound products, is drawn mainly from the company’s own wells. Water consumption is reduced through various efficiency-enhancing measures or through closed-cycle systems. As regards packaging material, the main focus is on avoidance, the use of ecologically safe materials and recovery within the framework of sustainable construction site management.
Social aspects in production
The main issues relating to social responsibility in production in this business unit, as well as in all others, are the safety and health of employees, business ethics and compliance. Additional aspects are described in the chapters “Employees” and “Social Responsibility”.
Sustainability in period of use and at end-of-life
In the case of concrete pavers, sustainability means a long service life, a high level of resistance, easy repairs and easy cleaning. These requirements are met through high quality, a protective surface finish and the possibility of exchanging individual pavers even after the finishing layer has been applied. The products should help to prevent user accidents. For pedestrians, Semmelrock products should be slip-proof. Solutions for people with special needs, such as guiding systems for the blind, are possible. Semmelrock pavers and slabs have a soilsealing effect and an influence on acoustics and on the micro-climate. Soil sealing can be reduced by making the products water-permeable. Negative acoustic effects, such as road traffic noise and echo effects in an urban environment, can be reduced through appropriate product design. Climate change results in higher summer temperatures in towns. Concrete surfaces tend to store heat and contribute to this effect. These aspects represent considerable challenges to be addressed through product innovation. Near-natural materials should also be used for accessories, such as paver joints, adhesive mortar or joint sand stabilizers. For design elements, such as pavers with integrated LED lighting, relevant eco-design principles apply.
Semmelrock has hardly any influence on the construction and demolition phase in the life cycle of its products. During demolition, care should be taken that concrete is properly separated from other materials and free of contamination. If these requirements are met, re-use as subgrade material in road construction is possible. Fine-grained, processed recycling concrete can also be used as a secondary raw material for new concrete products. However, maintaining the desired level of product quality is a considerable challenge. For the time being, the amounts of recycled material from construction debris re-introduced into the Semmelrock production process are insignificant.