Flexural beam fatigue strength evaluation of crushed brick as a supplementary material in cement stabilized recycled concrete aggregates

Abstract

In recent years, efforts have been made by various researchers to explore the sustainable use of Construction and Demolition (C&D) materials as a construction material in civil engineering applications. Recycled crushed brick is a commonly found material from demolition activities and works to date on this material in pavement applications have been limited to its usage in unbound pavement layers. This research was undertaken to evaluate the performance of crushed brick as a supplementary material in cement stabilized recycled concrete aggregates. An extensive suite of tests were undertaken on the crushed brick and recycled concrete aggregate blends stabilized with 3% cement. The laboratory evaluation comprised pH, plasticity index, foreign materials content, particle size distribution, linear shrinkage, California Bearing Ratio, modified Proctor compaction, Repeated Load Triaxial test, Unconfined Compressive Strength Test and Flexural Beam Tests. The cement stabilized blends with up to 50% crushed brick content and 3% cement were found to have physical properties, which comply with the local state road authority requirements. The results of Repeated Load Triaxial tests indicated the Recycled Crushed Aggregate/Crushed Brick (RCA/CB) blends performed well with 50% Crushed Brick (CB) content just on the border line for bound pavement material. Unconfined Compression Strengths met the minimum requirement for 7days of curing for all blends, while the 28 day strength of the blends also improved significantly. The results of the flexural beam tests were noted to be consistent with past works with cement stabilized quarry produced crushed rock products. The modulus of rupture and flexural modulus for all the cement-stabilized blends were found to be consistent with the previous works, which indicate that these blends are suitable for applications such as cement-stabilized pavement subbases. The fatigue life was also within the range that has been previously reported for quarry materials. The cement-stabilized blends with crushed brick as a supplementary material with up to 50% brick content and 3% cement were found to have physical and strength properties, which would comply with road authority requirements.