CPS sites shall employ a strategic mix of decorative pavement at key moments, like entrances and prominent pedestrian routes, alongside lower cost materials such as asphalt in more extensive paving areas. Whenever possible, pavement shall be pervious; have an initial solar reflectance (SR) value of at least 0.33, and shall complement the design intent regarding circulation, rainwater storage, accessibility, and program. Budgetary constraints have a major impact on paving material selection, and care shall be taken to maximize preferred
materials while keeping costs manageable.
Concrete
Concrete pavement’s durability, high albedo, and flexibility of use make it a very common material choice for CPS sites. As an impermeable surface, careful consideration shall be exercised regarding its context and related stormwater requirements. Depending on these factors, it may be necessary to limit the amount of concrete on site. This shall be considered on a case-by-case basis.
- Specialty concrete
Integral colored concrete, stamped concrete, and other textured finishes may be employed on CPS sites (only with CPS approval) and are suitable for limited use at entrances and other key program areas. Special consideration shall be taken when specifying specialty concrete per the following:- Many of the available surface patterns are rough and ill-suited for small children and wheelchair users
- The material may not be able to withstand the detrimental freeze-thaw conditions of the Chicago climate
Asphalt
Bituminous asphalt pavement shall be considered the least preferred material choice for CPS sites. It is an impermeable surface with a low albedo, contributing to both rainwater runoff and the urban heat island effect. When budget constraints do not allow for the use of other materials, asphalt may be used, but shall be limited as much as possible.
- Asphalt sealants: CPS requires asphalt paving to be sealed to protect against the elements and maintain longevity over time.
- Rubber-coated asphalt (athletic applications): For athletic tracks, and depending on budget, asphalt shall be coated with a rubber layer to ensure the health and safety of users.
Stabilized Aggregate
Aggregate with a stabilizing binder course below can be a good material choice for outdoor classrooms, garden paths, or other casual seating areas in schoolyards. Stabilized aggregate is considered a permeable surface and meets ADA standards for accessible surfaces, making it a great paving material choice for CPS sites. Due to the loose nature of aggregate and the tendency for small stones to travel, adjacency to turf fields, tracks, rubber surfacing, and main walks shall be avoided.
Permeable Pavement
Whenever possible, CPS sites shall maximize the amount of permeable surfacing where pavement is needed to reduce runoff and capture precipitation onsite. Permeable pavement is a component of larger site rainwater management strategies and shall be incorporated to maximize function of the entire system.
Including permeable pavement at entries or other key pedestrian routes allows for educational opportunities to learn about these systems, especially when combined with signs. Coordination with maintenance providers will be needed to prevent damage to permeable pavement systems with snow plows, and to coordinate periodic clean outs.
- Permeable Unit Pavers
Concrete unit pavers or clay brick pavers arranged with gaps and porous infill materials are a preferred paving material (with CPS approval) in CPS schoolyards due to their permeability and design flexibility. They are appropriate only when soil boring and infiltration testing results indicate adequate infiltration rates. Caution and careful design shall be exercised to ensure ADA compliance and prevent any pavers from being easily removed by hand. - Permeable Concrete
Permeable concrete is not recommended for all CPS sites and shall be considered on a case-by-case basis. If permeable concrete is integrated (per CPS approval) to meet rainwater management requirements, special care needs to be taken to ensure proper maintenance. If possible, locate permeable concrete in areas of low use.
See Volume 3 Section 1.5.1 Rainwater Management & Site Drainage for additional guidelines.
Poured-in-Place Protective Surfacing
Poured-in-place rubber surfacing is the preferred safety surfacing for all playgrounds on CPS sites. Playground surfacing design and colors shall be selected by the school and site designer. All designs shall employ no more than three colors with color mixes containing at least 50% black granules for increased color longevity. Protective surfacing shall also be used on playground mounds, but the subsurface profile shall contain a layer of concrete for structure. The profile of rubber surfacing shall deepen at playground fall zones and comply with Public Playground Safety Handbook (U.S. Consumer Product Safety Commission), ASTM F1292, and ADA standards.
See Volume 3 Section 1.4.4 Playgrounds for additional design considerations.
(See Figures 1.6.1_4 & 1.6.1_5)