Users of these computer programs should be aware that the fatigue curve traditionally used in Roller Compacted Concrete pavement design is more conservative than the fatigue curve traditionally used in conventional concrete pavement design. Some engineers use WinPAS computer program as a check on the StreetPave program or ACI tables. For pavements carrying mixed-vehicle traffic, design tools suitable for undoweled conventional concrete pavements-such as the ACI tables or American Concrete Pavement Association’s StreetPave computer program-can generally be used with satisfactory results. This is the approach used by the PCA procedure and the USACE procedure. For heavy-duty industrial pavements, which carry heavy industrial vehicles such as loaders or container haulers, the design may be based on the expected number of load repetitions of the single heaviest vehicle, and other vehicles that are significantly lighter can be ignored. The pavement thickness is a factor of the subgrade support, the Roller Compacted Concrete flexural strength and the anticipated vehicle loading.įor structural design purposes, Roller Compacted Concrete pavements fall into two main categories-heavy-duty industrial pavements and pavements carrying mixed-vehicle traffic. Therefore, the same design methodology used for conventional concrete can be applied to Roller Compacted Concrete pavements. Research has shown that Roller Compacted Concrete exhibits fatigue behavior very similar to that of conventional concrete. Since the critical stresses in Roller Compacted Concrete are flexural, fatigue due to flexural stress in used for thickness design. In Roller Compacted Concrete structural design, the pavement thickness is increased or the strength of the concrete is increased until the stress ratio is reduced sufficiently to provide for adequate fatigue performance. The tensile stress at the bottom of the concrete slab is affected by the applied load, tire pressure and spacing, concrete thickness and stiffness, and the characteristics of the supporting materials. In the structural design, the pavement thickness is a function of the expected loads, concrete strength, and characteristics of supporting base and subgrade. The strategy requires keeping the pavement’s flexural stress and fatigue damage caused by wheel loads within allowable limits. Thickness design for Roller Compacted Concrete pavements employs the same basic strategy as for conventional concrete pavements.
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