This study advances understanding of how selective demolition combined with advanced recycling techniques affects the quality of recycled concrete aggregates (RCA) from Dutch infrastructure concrete under industrial conditions. A 60-year-old highway viaduct in the Netherlands was selectively demolished, including T-beams, columns, abutments, and foundations. Powder, fine, and coarse RCA fractions were produced from these preselected members using a conventional impact/rotor crusher and two advanced recycling technologies (Smart Liberator and Mangeler) and compared with RCA obtained from unknown-origin concrete rubble. Experimental relationships were established between adhered mortar content and key physical, mechanical, and chemical properties of RCA across particle size fractions. Selective demolition combined with advanced recycling produced materials with substantially improved performance. Fine RCA (0–4 mm) exhibited water absorption values of 2–6%, compared to approximately 8% for fine RCA from unknown-origin concrete rubble, while coarse RCA (4–22 mm) reached 1.5–4%. These improvements were accompanied by the high-performance characteristics of RCA produced using the Smart Liberator, including a Los Angeles abrasion value of approximately LA15 and particle density up to 2610 kg/m³. The results highlight the importance of both parent concrete selection and the choice of comminution technique in achieving high-quality RCA. Unlike conventional high-energy impact crushing, advanced recycling relies on controlled friction, shearing, and selective abrasion, which preserves aggregate integrity and allows efficient removal of adhered mortar. The resulting RCA exhibits mechanical and physical performance comparable to natural aggregates and meets Eurocode 2 requirements. This study demonstrates, at full industrial scale and within a single reinforced concrete structure, how selective demolition combined with advanced recycling enables direct control over adhered mortar content and aggregate performance, narrowing the gap between conventional RCA and natural aggregates for high-performance structural applications.

This paper presents the measurement and analysis of energy consumption of a laboratory jaw crusher during concrete recycling. A method was developed to estimate the power requirements of a lab-scale jaw crusher. The impact of material properties on the crusher performance is studied. Eight concrete strength classes (C20/25–C80/95) were considered in the approach. Concrete specimens were cured for 28 days; at which time, concrete properties were obtained through tests such as bulk density, compressive strength, tensile strength, rebound number and ultrasonic pulse velocity. The impact of different aperture size (5 mm and 25 mm) on the energy consumption was also studied. From the experimental results, it is demonstrated that there is a strong dependance of energy consumption on the compressive strength of concrete. Energy of crushing for specimens with a 90 MPa compressive strength was four times higher than the energy needed to crush specimens with a 28 MPa compressive strength. Furthermore, the crushing requires three times more energy when the smaller aperture size is used to process concrete specimens. The results of this study can form a basis for a future large-scale field analysis and a detailed determination of the energy and economic efficiency of concrete recycling.

Over the last century, over one hundred crack width formulas have been developed to calculate the width and spacing of cracks in reinforced and prestressed concrete elements. It is unclear which formulas are the most accurate. An extensive comparison study is required to determine which formulas accurately describe the crack patterns, consisting of the crack width and spacing. To make such a study possible, this paper proposes categorizing formulas. The categorization of the formulas is based on their applicability, crack pattern representation, and background. The categorization presents an overview of the different assumptions and application areas for describing crack patterns.

Acoustic emission (AE) signal parameters can be used to classify the source type in concrete structures. However, signal parameters are influenced by the wave propagation from the source to the receiver, leading to wrong source classification results, especially for monitoring large concrete structures. This paper experimentally evaluates the influence of wave travel distance on signal parameters on a full-scale shear test of a reinforced concrete beam. The evaluated signal parameters include the RA value, average frequency, peak frequency, frequency centroid, and partial power. The evaluation reveals the limitation of using RA value - average frequency trends in large scale structural concrete members. Based on the evaluation, we propose a new source classification criterion using peak frequency or partial power, which can effectively classify the source type. The new criterion is also validated in a reinforced concrete slab test, which is another structural type. Based on the new criterion, we suggest a sensor layout that is suitable for source classification for large concrete structures. The results of this paper can help developing a reliable solution for real-time source classification for large concrete structures in general.