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Permeable pavement is utilised in order to alleviate flooding in towns, cities and other urban areas, but it is prone to clogging, has relatively low strength and requires regular maintenance. We have developed a novel permeable pavement with low tortuosity pore structure that can be cast on-site that is not only resistant to clogging, but also has high permeability and strength. This high strength clogging resistant permeable pavement (CRP) was prepared by introducing straight pore channels of varying size and number into self-compacting mortar. Samples with porosity ranging from 2 to 32% were tested. In all cases, permeability and compressive strength were substantially higher than conventional permeable concrete. More significantly, CRP can be engineered with low porosity (5%), high strength (> 50 MPa) and high permeability (> 2 cm/s), but does not clog despite extensive cyclic exposure to flow containing sand and clay. A simple method to model the permeability of CRP from the pore structure is described. We report for the first time a high strength clogging resistant permeable pavement capable of retaining sufficient porosity and permeability for storm-water infiltration without requiring frequent maintenance. This innovative system will help alleviate urban flooding and contribute towards a more sustainable urbanisation. [ABSTRACT FROM AUTHOR]

Permeable concrete is used to reduce urban flooding as it allows water to flow through normally impermeable infrastructure. It is prone to clogging by particulate matter and predicting the long-term performance of permeable concrete is challenging as there is currently no reliable means of characterising clogging potential. This paper reports on the performance of a range of laboratory-prepared and commercial permeable concretes, close packed glass spheres and aggregate particles of varying size, exposed to different clogging methods to understand this phenomena. New methods were developed to study clogging and define clogging potential. The tests involved applying flowing water containing sand and/or clay in cycles, and measuring the change in permeability. Substantial permeability reductions were observed in all samples, particularly when exposed to sand and clay simultaneously. Three methods were used to define clogging potential based on measuring the initial permeability decay, half-life cycle and number of cycles to full clogging. We show for the first time strong linear correlations between these parameters for a wide range of samples, indicating their use for service-life prediction. [ABSTRACT FROM AUTHOR]

The discrete element model considering media properties and interface differences was constructed for revealing the mesoscopic fracture characteristic of cemented rockfill in this study. The effects of aggregate strength and mass fraction on strength, deformation, energy and cracking of cemented rockfill were investigated. The results showed that the generally concerned two-element intergranular fracture between aggregates and cement matrix ITZ only plays a leading role in one fracture characteristic, but the failure induced by damaged aggregates is more severe than this fracture characteristic. The fracture characteristic transformation induced deterioration of cemented rockfill is catastrophic. The compressive strength of the specimen produced from 12.88 MPa gangue is nearly 30% worse than that of 32.77 MPa. And this fracture characteristic transformation is related to the aggregate mass fraction. The aggregate strength corresponding to the turning aggregate to cemented matrix strength ratio decreases from 52 MPa to 32 MPa with increasing the aggregate mass fraction from 42.7% to 57.7%. Therefore, the development of cemented rockfill requires more attention to the compatibility as characterized by the aggregates to cement matrix strength ratio and aggregate mass fraction. As the strength ratio increases, the recycled aggregates transform from defect clusters to load bearing phases in cemented rockfill. [ABSTRACT FROM AUTHOR]