Synthesis of design and construction practices
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- Figure 13. Initial Const and PW Costs for all Alternatives
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le x ib le CRCP Co m p o s it e w/ CTB Co m p o s it e w/ CRCP F le x ib le CRCP Co m p o s it e w/ CTB Co m p o s it e w/ CRCP Initial Cost Total PW of LCC Re la ti v e Co s t (w ith re s p e c t to th e lo w e s t a lte
rn a tiv e )
Figure 13. Initial Const and PW Costs for all Alternatives
In the case of the composite pavement with a CRCP base, the cost of the 200 mm (8 in) concrete base ($81.48 per m 2 [$66.00 per sq. yd]) is relatively high. With the computed thickness of the rigid slab using the AASHTO 1993 method for the CRCP pavement alternative, the price per square meter was $ 104.93 [$85.00 per sq. yd.], which accounts for the majority of the price difference between the composite pavement with CRCP base and the rigid pavement alternative.
Despite the noticeable difference in the PW costs obtained, there is an important consideration regarding composite pavements. According to the VDOT LCCA publication, a composite pavement with a CTB would be due for a reconstruction when year 50 is reached. However, Balbo and Cintra (1994) conclude that because CTB is originally produced with aggregates (i.e., it contains CTA) the material will behave like a very good granular material. 32 This suggests that a reconstruction may not be required; milling and replacement of the AC layer would be sufficient. However, reflection cracking is likely to occur. In the case of the composite pavement with CRCP base, a similar assumption can be made because only functional maintenance operations are performed on the asphalt course throughout its service life. In addition, the longevity of such pavement, due to the bituminous surface layer preserving the structure integrity of the base, suggests that reconstruction is not necessary. In brief, typical flexible and rigid pavements reach the end of their service lives after 50 years, at which time a reconstruction is likely to occur; however, composite pavements can last more than 50 years as long as maintenance and light rehabilitation operations are performed. tải về 1.81 Mb. Chia sẻ với bạn bè của bạn:
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