| 1. |
Many features of concrete pavements should be assessed when considering them from a sustainability perspective. Further, innovative features continue to emerge that result in additional enhancement to the sustainability of concrete pavements. Fig. 2.4 illustrates. |
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Features of concrete pavements that can be enhanced sustainability |
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A piece of road cut out. |
| 2. |
Fig. 3.1 illustrates |
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Finite element stress model of the road surface during the high traffic times |
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Heat radiation model of the road during high traffic times |
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Variability of transverse tined surface and it effect on noise level. |
| 3. |
Many States use either asphalt or cement-stabilized bases for strong erosion-resistant bases. |
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True |
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False |
| 4. |
Two-lift pavements are constructed in two lifts, wet on wet, using two slipform pavers one immediately following the other. The concrete mixture in the bottom lift is often different from the mixture in the top lift. |
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True |
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False |
| 5. |
Figure 3.2 is a |
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RCC pavement being placed |
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Two-lift pavement being placed |
| 6. |
A two lift concrete paving is typically consist of a |
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Thick bottom lift (typically 80 percent or more of the total thickness) and a thin (20 percent or less of the total thickness) top lift that is optimized for carrying traffic. |
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Two even layers of the same concrete placed wet on wet |
| 7. |
It is well established that the manufacturing of Portland cement (specified under AASHTO M 85/ASTM C150) is an energy intensive process, involving heating large quantities of finely ground rocks and minerals to very high temperatures (roughly 1400°C) to produce nodules called clinker that are then interground with gypsum to a fine powder; |
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roughly 700°C |
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roughly 1400°C |
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roughly 2000°C |
| 8. |
Light-weight aggregate (LWA) is normally a manufactured product, made by heating shale, clay, or slate in a rotary kiln to about 2000°F; see Figure 4.8. The final product is ceramic in nature and contains controlled amounts of air bubbles, thus |
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increasing aggregate porosity and reducing density |
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decreasing aggregate absorbency and reducing density |
| 9. |
Concrete used for pavement is produced at either a central mix plant (Figure 5.4) or a dry batch plant utilizing transit mix trucks (Figure 5.5). Regardless of the equipment used, it is imperative that the plant produce a concrete mixture that meets or exceeds specification requirements, is uniform within each batch, and is also uniform from batch to batch. Non-uniform concrete leads to non-uniform performance, which |
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in turn results in premature failure with related maintenance and rehabilitation costs. |
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does not make that much difference in the results. |
| 10. |
Concrete pavement surface textures provide the friction needed for safe roadways. Surface textures have also been shown to be the primary contributor to pavement-tire noise. |
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True |
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False |
| 11. |
Perhaps one of the most overlooked parts of the concrete paving process, curing has a significant impact on concrete pavement durability and thus on sustainability. In general, white pigmented curing compound should be applied _____________________. All exposed surfaces of the concrete pavement should be completely covered (the pavement surface should be uniformly white). Precautions should be taken to insulate the concrete during cold weather curing to prevent the pavement from freezing before gaining sufficient strength. |
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before any surface evaporation occurs. |
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after any surface evaporation occurs |
| 12. |
Sawed joints are necessary for non-reinforced pavements to prevent uncontrolled cracking. Practices for sawing and sealing joints vary across the United States. The most common options for green sawing concrete pavement are wet sawing with diamond blades (saw cut depth = T/4 or T/3) and early entry sawing using a dry diamond blade (saw cut depth = 1 in. to 3 in.).
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True |
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False |
| 13. |
Concrete pavement preservation treatments include the following (Smith, Hoerner, and Peshkin 2008):
- Slab stabilization
- Partial-depth repair
- Full-depth repair
- Use of precast panels in full-depth repairs
- Retrofitted edge drains
- Load transfer restoration
- Diamond grinding and grooving
- Joint resealing and crack sealing
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True |
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False |
| 14. |
Diamond grinding is applied to a concrete pavement after partial- and full-depth repairs and load transfer restoration, as well as slab stabilization and drainage retrofitting. Using gang-mounted, closely-spaced diamond saw blades, diamond grinding uniformly removes a thin layer of concrete, restoring |
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pavement ride quality |
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improving skid resistance. |
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All of the above |
| 15. |
Are pavements perfectly sustainable? |
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Yes |
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No. Like any other infrastructure system, their construction and maintenance consume nonrenewable resources, generate waste, and consume energy. |
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