Recycled clay brick containing materials as a raw material in resource efficient cements and durable concretes

Reports from national road authorities have indicated a significant interaction between the damage mechanisms of ASR and the frost resistance and freeze-thaw durability of concrete.

This IGF project aimed to systematically investigate the impact of deleterious ASR on concrete's frost and freeze-thaw resistance, and assess its practical relevance. The aim was to define the criteria and threshold values at which a significant reduction in frost or freeze-thaw durability could be expected.

The Stiffness Damage Test is an internationally applied method that is new to Germany. It enables the precise quantification of concrete damage. Tests on laboratory concrete samples and cores taken from damaged motorways revealed that the ratio of compressive strength to modulus of elasticity in damaged concrete increasingly deviates from the specified relationship in DIN EN 1992-1-1 [1] as the level of damage increases.

The aim of the project is to examine the utilisation opportunities of brick-containing materials derived from the recycling of mineral construction waste.

The objective is to develop and describe the technical possibilities of producing resource-efficient cements with processed brick-containing construction waste and reduced clinker content, thereby reducing process-related CO₂ emissions.

While using clay brick-based recycling building materials as pozzolanically reacting cement main constituents, high-performance cements as well as durable concretes can be achieved complying with the relevant assessment criteria in approval tests issued by the building inspectorate and proving the technical suitability for the application in the building industry.

The ecological and economic importance is based on the development of a cross-sectorial concept for the provision of technically and ecologically optimized construction products by closing material cycles within the industries of clay brick, recycling, cement and concrete.

VDZ is coordinating the overall project and is responsible for subproject 1: Durability of clay-brick containing concrete.