Generic ready-mixed concrete EPD
Institut Bauen und Umwelt e.V. (IBU) published an EPD for UK manufactured generic ready-mixed concrete. The EPD product is a generic 1 m3 of ready-mixed concrete and represents a global warming potential of 219 kg of CO2Eq for all life stages A1 to C4 inclusive.
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The product is a generic 1 m3 of ready-mixed concrete, where the constituent proportions are 310 kg of cementitious material, 1915 kg of natural aggregate, 137 litres of mains water, 2 litres of recycled water and 1.6litres of a chemical admixture. The fresh wet density is a representative 2380 kg/m3. With many sources of cementitious materials and natural aggregates this generic concrete can be assumed to be at a consistence class not less than S3 and strength class not less than C30/37.
Due to the wide variation of cements and natural aggregates available throughout the UK confirmation of consistence and strength class for any concrete should be confirmed by the producer before supply.
Ready-mixed concrete is made by mixing coarse and fine aggregates, cement and water in controlled proportions. Chemical admixtures are used to reduce water content and improve fresh and hardened concrete properties. Delivered to site on a just-in-time basis, ready-mixed concrete may be cast into any conceivable shape with almost no limit on volume. When hardened, concrete can carry substantial compressive loads by itself, but is more frequently reinforced to substantially increase its tensile and flexural strength.
Interrogation of the LCA results show that the cradle to grave GWP impact of a 1m³ of ready-mixed Concrete is 122.2 kg CO2e (Modules A1-C4).
For GWP, A1-A3 accounts for 137% of the lifecycle impact with carbonation in the use phase and post-demolition, reducing the overall impact of the ready-mixed concrete. Carbonation in the use phase alone reduces the GWP impact by 45%. Further analysis of the GWP figures show that the largest contributors to this value are cement (41%), utilities (30%) and the aggregates and powders used in production (24%).
The full results across all LCA indicators can be found within the EPD document.