Re-generating (raw) materials and end-of-life products for re-use in Cement/Concrete

The main goal of the proposed project titled, “RE-generating (raw) materials and end-oflife products for reuse in CEMENT/Concrete (RECEMENT)” is to provide low-energy, low CO2 and low-cost alternative binding materials by re-generating end-of-life (EOL) materials mined urban construction and mineral deposit quarries for replacing ordinary Portland cement (OPC). Environmental concerns of CO2 emission from OPC production have led to partial substitution of OPC by supplementary cementitious materials (SCMs) such as fly ash, slag, and silica fume. Despite their satisfactory performance in concrete, their limited availability restricts their impact on the circular economy. Finding new alternative SCMs of wider availability would reduce Portland clinker use in cement production. When used directly, EOL materials, such as marble dust from quarries, do not contribute to hydration needed for setting and hardening in concrete and are limited to a filler function. However, effectively re-generated EOL materials may contribute to hydration processes and replace a substantial portion of OPC. The general objectives of RECEMENT contribute to the European Research Area (ERA) by :

(1) re-generating EOL material destined for landfill as the raw material for producing concrete;

(2) creating an economic value for large volumes of material of previously zero value, while reducing the energy consumption, CO2 emission, and the raw material cost of producing cement;

(3) advancing sustainable construction materials in Europe by reducing the raw material consumption and greenhouse gas emission from cement manufacturing, to meet EU2020 targets in the European Energy Sustainability Initiative;

(4) educating and training the next generation on recycling and re-use of EOL materials in the concrete industry. The proposed project aligns perfectly with the ERA-MIN2 call Topic 4 on Recycling and Re-use of End-of-Life products by transforming a linear economy (Figure 1a) of high-volume construction materials into a more
efficient circular economy (Figure 1b). Moreover, we are incorporating debris from other industries into this circular economy for the construction one, substantially broadening the environmental and economic impact of RECEMENT.

To achieve the above-mentioned goal and general objectives, the proposed RECEMENT project is designed around the following specific research objectives:

(1) Mining and re-generating recycled SCMs for binding agents: Collect and characterize chemical and physical properties of EOL materials mined from construction, ceramic and quarry sites that can be used as SCMs in cement-based materials. Determine the thermal/mechanical treatments to re-activate the EOL materials. Qualitative evaluation of pozzolanic (or hydraulic) behaviour of re-generated SCMs.

(2) Performance evaluation of cement- based materials including re-generated SCMs: Analyse the influence of replacing OPC with regenerated SCMs (up to 30% by weight) on setting, workability, rheology, compressive strength, water absorption and chemical composition of cementbased materials.

(3) Durability of concrete including re-generated SCMs: Evaluate durability of new concrete in terms of sulfate attack, alkali silicate reaction (ASR), and corrosion resistance. Determine the relationships between source and mineralogy of EOL materials, pozzolanic behaviour of re-generated SCM, and their dosage in cement with performance and service life of mortar containing re-generated SCMs.

(4) Assessing eco and economic impact of re-generated SCMs: Develop an integrated life-cycle analysis (LCA), life-cycle costing (LCC) and Cost-Benefit Analysis (CBA) to understand the social, economic and environmental impacts of replacing OPC with re-generated SCMs and to foresee barriers to adoption.

(5) Dissemination and exploitation for maximum impact: Increasing the socio-economic impact of RECEMENT by elaborating the RECEMENT innovation to the chain of end-users.