Cementitious porous pavement in stormwater quality control: pH and alkalinity elevation

Abstract

A certain level of alkalinity acts as a buffer and maintains the pH value in a stable range in water bodies. With rapid urban development, more and more acidic pollutants flow to watersheds with runoff and drop alkalinity to a very low level and ultimately degrade the water environment. Cementitious porous pavement is an effective tool for stormwater acidic neutralization. When stormwater infiltrates cement porous pavement (CPP) materials, alkalinity and pH will be elevated due to the basic characteristics of cement concrete. The elevated alkalinity will neutralize acids in water bodies and maintain the pH in a stable level as a buffer. It is expected that CPP materials still have a certain capability of alkalinity elevation after years of service, which is important for CPP as an effective tool for stormwater management. However, few previous studies have reported on how CPP structures would elevate runoff alkalinity and pH after being exposed to rainfall-runoff for years. In this study, three groups of CPP specimens, all exposed to rainfall-runoff for 3 years, were used to test the pH and alkalinity elevation properties. It was found that runoff pH values were elevated from 7.4 to the range of 7.8-8.6 after infiltrating through the uncoated specimens, and from 7.4 to 8.5-10.7 after infiltrating through aluminum-coated specimens. Runoff alkalinity elevation efficiencies are 11.5-14.5% for uncoated specimens and 42.2% for coated specimens. The study shows that CPP is an effective passive unit operation for stormwater acid neutralization in our built environment.

A novel cementitious microfiltration membrane: mechanisms of pore formation and properties for water permeation

“…For example, larger aggregates were mixed with smaller cement particles to produce a pervious pavement, which was used to transport large volumes of water through the material structure to eliminate the problems of storm-water runoff and rainwater acidication. [26][27][28] Therefore, in this study, the uniformly larger quartz particles were added to the system of cement and water. The quartz particles could disrupt the growth of the cement hydration products and thereby increase the porosity and pore size of this novel cementitious membrane.…”

Enhanced containment of polycyclic aromatic hydrocarbons through organic modification of soils

“…For example, pervious pavement has been used to reduce both the volume and contaminant load in storm runoff . In addition, pervious concrete pavements can elevate pH of runoff from acidic nature . However, conventional pervious pavements systems have a limited contaminant removal capacity .…”

Coupled infiltration and filtration behaviours of concrete porous pavement for stormwater management

“…Cementitious porous pavement (CPP) is a structural low‐impact development material for rainfall–runoff management. CPP is an available and effective approach to mitigate these problems through gravitational drainage, capillary movement, infiltration and filtration mechanisms (Isenring et al ., ; Jimenez and Perez, ; Fach et al ., ; Jackson and Ragan, ; Kuang et al ., , (1); Kuang and Sansalone,; Sansalone et al ., ). A variety of in situ structural best management practices or unit operations and processes have been developed for stormwater quality and quantity control through infiltration/filtration and some degree of exfiltration (Colandini et al ., ; Hogland et al ., ; Kuang et al ., , (2), ; Sansalone et al ., ).…”

“…When more and more particles are strained on CPP surface, the pore structure is able to remove finer particles in a higher capacity (Kuang et al ., 2007b; Niemczynowicz and Hogland, ; Sansalone et al ., , ). The mechanism of filtration removes not only sandy and silt particles from runoff but also nutrients, heavy metals and other pollutants associated with those particles (Pagotto et al ., ; Sansalone et al ., ; Kuang and Sansalone, ). Experimental study verified that the suspended particulate matter measured as total suspension solids can have a mass removal efficiency up to 90%, total phosphorus up to 65% and total nitrogen up to 80% (Kuang et al ., 2008; Kuang and Sansalone, ; Park and Tia, ; Sansalone et al ., ; Teng and Sansalone, ).…”

“…The mechanism of filtration removes not only sandy and silt particles from runoff but also nutrients, heavy metals and other pollutants associated with those particles (Pagotto et al ., ; Sansalone et al ., ; Kuang and Sansalone, ). Experimental study verified that the suspended particulate matter measured as total suspension solids can have a mass removal efficiency up to 90%, total phosphorus up to 65% and total nitrogen up to 80% (Kuang et al ., 2008; Kuang and Sansalone, ; Park and Tia, ; Sansalone et al ., ; Teng and Sansalone, ). However, the mechanism of filtration also may result in CPP surface clogging (Andersen et al ., ; Bäckström and Bergström, ; Kuang et al ., 2008).…”