PSI - Issue 70

Charumathi Manickam et al. / Procedia Structural Integrity 70 (2025) 564–571

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field applications, by Hsu et.al (2011). High porosity pervious concrete demonstrated high water permeability, by Ravindrarajah et.al. (2010). Permeability of pervious concrete helps in infiltrating the runoff water from the road surface. As shown in the study it remains effective even under partial clogging conditions. 6.2 Clogging: Pervious concrete pavement revealed that both sand and clay (sodium montmorillonite) cause significant clogging, with clay being about ten times more clogging than sand by mass. While pressure washing did not fully restore infiltration rates, the infiltration and exfiltration rates of the system remained higher than the required levels for a 100 year storm event in Denver. However, the study found that the primary flow-limiting factor was the subgrade, not the pervious concrete itself, as most of the head loss occurred in the subgrade, a thin layer of sand with high hydraulic conductivity. Thus, while pervious concrete is effective for stormwater detention with an engineered drainage system, infiltration performance of the subgrade depends heavily on exfiltration capacity, by Patrick Coughlin et.al. (2012) Pervious concrete pavements require little upkeep and work effectively in preventing clogging of the void structure. To prevent adjacent landscaping from directing items such as soil, rock, leaves, or garbage onto the pavement, which might impede water flow, proper site preparation is crucial. To eliminate surface material, annual vacuuming or more frequent cleaning may be required. Power blowing and pressure washing are further alternatives. In certain instances, pressure washing has been demonstrated to restore 80% to 90% of permeability; nevertheless, pervious concrete management techniques are still developing, by Paul Tennis et.al. (2019). The angularity number of coarse aggregate is a metric that represents the angularity and form of the aggregate particles. With bigger aggregate sizes, the angularity number grew. Permeability increased from 0.4 cm/sec to 1.26 cm/sec within the same range, while compressive strength varied from 10 N/mm² to 26 N/mm² as the angularity number varied from 8 to 4, by Uma Maguesvari et.al. (2013). 6.4 Compressive Strength and Void Ratio: The compressive strength of porous concretes diminished as the total void ratio decreased, regardless of the type of concrete or aggregate size. For porous concretes with a void ratio ranging from 15% to 30%, there was an almost linear correlation between compressive strength and void ratio, by Aamer Rafique Bhutta et.al. (2012). The pervious concrete compositions have an average porosity of 33%. High porosity pervious concrete demonstrated low compressive strength, by Ravindrarajah et.al. (2010). One of the main problems is that pervious concrete does not perform well in heavy loads or cold temperatures due to problems including clogging, reduced strength, damage from freeze-thaw cycles, and shorter lifespan. Load carrying capacity of pervious concrete is low, by Mohamed Ahmad et.al. (2019). 6.5 Incorporation of Natural Fibres in the Eco-Drainage System Natural fibres like coconut fibre and hemp fibre can be added to conventional concrete, improving the strength and environment. They can be replaced instead of reinforcement, natural fibres are an eco-friendly option. improve crack resistance, and contribute to a more ductile failure mode. The following are the factors considered for the application of natural fibres in drainage slabs. 6.5.1 Fibre Length and Content Ratios for Concrete in Drainage Applications Optimal fibre lengths and content ratios improve water percolation through slabs, making them highly suitable for drainage systems. This permeability allows for controlled water infiltration, reducing surface runoff and lowering flood risks in urban areas. At 0% fibre content, the average compressive strength of plain concrete was measured at 60.19 N/mm². The findings showed that compressive strength decreased with increasing fibre amount, with the 6.3 Angularity Number of Aggregate