This blog provides a clear, concise, and cohesive presentation of cement-bound materials options for 10 specific engineering pavement applications: new concrete pavements, concrete overlays, pervious concrete, precast pavements, roller-compacted concrete, cement-treated base, full-depth reclamation with cement, cement-modified soils, recycled concrete aggregates, and repair and restoration. Each application is presented as a method for meeting specific design and construction objectives that today’s pavement practitioners must accomplish. The benefits, considerations, brief description, and summary of materials, design, and construction requirements, as well as a list of sustainable attributes, are provided for every solution.
New Concrete Pavements
New concrete pavements include both jointed and continuously reinforced concrete pavements. Thicknesses can range from 6 to
15 inches, depending on traffic, environment, and soils.
Objectives
- Provide long life and reduced maintenance.
- Improve the surface.
- Provide high load-carrying capacity.
- Expedite construction/renewal.
- Reduce urban heat island effect.
- Increase light reflectance.
- Provide a sustainable option
Benefits
- It can withstand many environments.
- It typically lasts much longer than their original design life.
- Concrete pavement surfaces reflect light and reduce the urban heat island effect.
- Vehicle fuel consumption for the driving public is reduced on concrete surfaces.
Typical Applications
- Highways
- Streets and Local
- Roads
- Shoulders
- Commercial/
- Lightweight
- Airfields
- Heavy Industrial
Concrete Overlays
Overlays are a method of rehabilitating and/ or increasing the structural capacity of existing pavements. Bonded overlays are thin (2- to 6-in.) layers of concrete bonded directly to a sound underlying pavement in order to increase structural capacity. Unbonded overlays are used principally when the underlying pavement is in fair to poor condition and are thick (4 to 11 in.) enough to support the traffic loads but recognizing the structural capacity of the underlying pavement.
Objectives
- Extend pavement life.
- Improve the surface.
- Increase load-carrying capacity.
- Expedite construction/renewal.
- Reduce urban heat island effect.
- Increase light reflectance.
- Provide a sustainable option.
Benefits
- Reconstruction costs are
- avoided.
- Construction of an overlay
- is much faster than
- reconstruction.
- Concrete pavement surfaces
- reflect light and reduce the
- urban heat island effect.
Typical Applications
- Highways
- Streets and Local
- Roads
- Shoulders
- Commercial/Lightweight
- Airfields
- Heavy Industrial
Pervious Concrete
Pervious concrete is a paving material consisting of almost exclusively coarse aggregate, but with sufficient cement paste to bind the mixture into a strong but open (porous) material with exceptional drainage properties.
Objectives
- Satisfy EPA Storm Water Phase II regulations.
- Earn LEED credits.
- Improve safety.
- Reduce tire-pavement noise.
- Provide a sustainable option.
Benefits
- Pervious concrete is an EPA Best Management Practice.
- Storm water runoff and flash flooding is minimized.
- Hydroplaning and splash and spray are minimized.
- Noise from the tire-pavement interaction is reduced.
- Pervious concrete surfaces reflect light and help reduce the urban heat island effect.
Typical Applications
- Streets and Local Roads
- Shoulders
- Commercial/Lightweight
Precast Pavements
Precast pavements are a technique for constructing or repairing a concrete pavement surface where casting and curing of panels
are done in advance. Precast pavements are a highly durable finished pavement and not just a temporary fix. They are a repair option for jointed concrete pavements (JCP) or reconstruction option for both JCP and HMA pavements. Rapid placement of the hardened panels can then be conducted within short traffic closure windows.
Objectives
- Provide long life.
- Improve the surface.
- Provide high load-carrying capacity.
- Expedite construction/renewal.
- Provide a sustainable option.
Benefits
- Construction can be completed during short (overnight or weekend) closures.
- Lane closures and associated user delays during construction are minimized.
- Precast pavements are a highly durable finished pavement and not just a temporary fix.
- Precast pavement surfaces reflect light and help reduce the urban heat island effect.
Typical Applications
- Highways
- Airfields
- Heavy Industrial
Roller-Compacted Concrete
Roller-compacted concrete (RCC) is a stiff and strong concrete mixture that is typically placed with asphalt pavers as either a surface or a support layer. Roller-compacted concrete surfaces can be used for low-speed or industrial applications. Roller-compacted concrete layers can also serve as a support layer to a thin (1.5- to 2-in.) HMA (or occasionally concrete) surface.
Objectives
- Provide low-cost option.
- Provide high load-carrying capacity.
- Expedite construction.
- Allow early opening to traffic.
- Provide a sustainable option.
Benefits
- Roller-compacted concrete provides a strong, dense, and durable material that can be quickly constructed.
- Construction is fast with no forms or finishing.
- No steel reinforcement and minimum labor make RCC economical.
- For many applications, joint sawing is optional for aesthetic purposes resulting in additional cost savings.
- Roller-compacted concrete pavement surfaces reflect light and help reduce the urban heat island effect.
Typical Applications
- Highways
- Streets and Local Roads
- Shoulders
- Airfields
- Commercial/Lightweight
- Heavy Industrial
Cement-Treated Base
Cement-treated base (CTB) is a mixture of aggregate material and/or granular soils combined with engineered amounts of portland cement and water that hardens after compaction and curing to form a stronger, stiffer, and more durable paving material. Cement-treated base is used as a pavement base for flexible pavements or a subbase for concrete pavements.
Objectives
- Provide a strong, uniform base/ subbase for current and future loading conditions using in-place or locally available marginal soils and granular material.
- Reduce stresses on the subgrade.
- Stabilize a variety of soils with a single stabilizer.
- Reduce rutting and deflections in a flexible pavement surface.
- Improve the structural capacity of the existing soil.
- Provide a sustainable option
Benefits
- A stiffer base reduces deflections due to traffic loads, thereby extending pavement life.
- Subgrade failures, pumping, rutting, joint faulting, and road roughness are reduced.
- Base thickness is reduced compared to unbound granular base thicknesses.
- Marginal aggregates, including recycled materials, can be used, thus reducing the need for virgin, high-quality aggregates.
Typical Applications
- Highways
- Streets and Local Roads
- Shoulders
- Airfields
- Commercial/Lightweight
- Heavy Industrial
Full-Depth Reclamation
Full-depth reclamation (FDR) is a technique in which hot-mixed asphalt (HMA) material from the existing pavement is removed, combined with Portland cement, and used to create a new and improved base. The FDR base is then topped with a new HMA or concrete surface layer.
Objectives
- Provide a strong, uniform base/subbase for current and future loading conditions using existing failed asphalt surface and base material.
- Maintain existing grade with minimum material removal or addition.
- Reduce or totally eliminate the need for virgin aggregates.
- Reduce stresses on the subgrade.
- Reduce rutting and deflections in a flexible pavement surface.
- Improve the structural capacity of stabilized base over unstabilized base material.
- Provide pavement reconstruction method that is fast and minimizes traffic disruption.
- Provide a sustainable option.
Benefits
- The performance of the base layer is improved over an unbound granular base.
- Little, if any, material is hauled off or onto the site, resulting in less truck traffic, lower emissions, and less damage to local roads. Work can be completed quickly compared to removal and replacement techniques.
- Full-depth reclamation process is economical compared to removal and replacement and thick overlays.
Typical Applications
- Highways
- Streets and Local Roads
- Airfields
- Commercial/Lightweight
- Heavy Industrial
Cement-Modified Soils
Cement-modified soils (CMS) are soils and/ or manufactured aggregates mixed with a small proportion of Portland cement. Cement modified soils exhibit reduced plasticity, minimized volumetric changes due to moisture changes, increased bearing strength, and improved stability.
Objectives
- Reduce the plasticity and high-volume change characteristics of clay soils due to moisture variations.
- Improve stability of a poorly graded sandy soil. Improve the properties of a sandy soil containing a high plasticity clay.
- Provide a method to dry out a wet subgrade.
- Provide a firm construction platform to work on.
- Provide a sustainable option.
Benefits
- Cement-modified soils provide a weather resistant work platform for construction operations.
- Fatigue failures caused by repeated high deflections are controlled.
- There is a reduction in moisture sensitivity and subgrade seasonal load restrictions.
- No mellowing period is needed as required by other stabilizing agents.
Typical Applications
- Highways
- Streets and Local Roads
- Shoulders
- Airfields
- Commercial/ Lightweight
- Heavy Industrial
Recycled Concrete Aggregates
Recycled concrete aggregates (RCA) are aggregates produced from the recycling of existing concrete. Existing concrete is removed, processed into appropriate aggregate sizes, and reused in various pavement applications.
Objectives
- Recycle excavated concrete road.
- Minimize construction cost.
- Reduce dependence on good quality virgin aggregates, which may be hard to find or expensive to bring in.
- Provide a sustainable option.
Benefits
- Recycled concrete aggregates are versatile because they can be used in any pavement layer.
- Material costs are reduced.
- Construction time can be expedited with on-site recycling plants.
- Roads suffering from ASR or D-cracking can be recycled instead of discarded.
- The need for old concrete disposal is reduced.
Typical Applications
- Highways
- Streets and Local Roads
- Shoulders
- Airfields
- Commercial/Lightweight
- Heavy Industrial
Repair and Restoration
Repair and restoration is a series of techniques including diamond grinding, dowel bar retrofit, full and partial depth repairs, joint sealing, patching, and slab stabilization that extend the life of a concrete road. These techniques can often be used in lieu of
resurfacing or reconstructing.
Objectives
- Extend life.
- Improve the surface.
- Expedite construction/renewal.
Benefits
- Repair and restoration fixes distressed concrete road (Comment—areas may not be isolated, i.e., diamond grinding an entire roadway).
- These are options for low-cost concrete road life extensions.
Typical Applications
- Highways
- Airfield
- Streets and Local Roads
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Mini Tractor