“Case Studies of Different Types of FRC Pavement Projects”
by Juan Pablo Covarrubias, Director-TCPavements and Director-ISCP
Fiber-reinforced concrete (FRC) has been used in pavements with optimized geometry, rendering excellent results from a technical point of view and in an economical way. Fibers increase slab capacity fatigue life, especially when cracks propagate from the bottom of the slab—a typical failure mode for short slabs. Due to this fact, and to the experimental results of several test sections and real projects, FRC has been used successfully in Thin Concrete Pavements and Ultra-Thin Concrete Pavements technology (U-TCP) in many projects in Chile, South America, allowing the construction of fiber reinforced concrete pavements for different applications between 8 and 23 cm thick (3.1 and 9 in thick). This article correlates with the Next ISCP/ACPA Webinar in Series is on FRC: “Fiber-Reinforced Concrete Pavements” to be Held May 30, 2019. (Click each photo below to enlarge).
PROJECT REVIEW in CHILE:
Ruta 60-CH, Camino La Pólvora: This 2016 project was paved in 23 cm (9 in) of unbonded FRC over the existing deteriorated asphalt pavement. This route allows the access of heavy traffic to an important port in Chile. The section paved in concrete with optimized slabs, corresponds to a replacement of 15 km (9.3 miles), which is currently the highest traffic demand in Chile, that has been built with this technology. It was designed for 189,000,000 ESALs for 20 years. The original solution was more than 30 cm (11.8 in) in traditional concrete as designed by AASHTO 98. A VIDEO of the pavement in use: https://www.youtube.com/watch?v=YqKWJIIxq0k.
Ruta 7, El Toqui: This pavement was built in 2011 with optimized slabs on the Ruta 7, next to Coyhaique in the south of Chile. This section was divided in four sections and each section was built with different types of fiber and without fiber. The thickness of the pavement is 11 cm and 13 cm (4.3 and 5.1 in) respectively, with a concrete of 40 MPa compressive strength, square slabs of 1.75 m (6 ft) and a widened slab of 20 cm (7.8 in) and Portland Cement Concrete (PCC) shoulder. The subbase was specified to be California Bearing Ratio (CBR) 50% of 10 cm (3.9 in) over a soil with support capacity of CBR 25%.
The design was made for 3,000,000 ESALs. As shown in the VIDEO, after 5 years, there are no fatigue cracks, settlement, or lateral displacement: https://www.youtube.com/watch?v=qqLBuvtH-jw.
Mahuidanche-
Mision Ingress: In 2012, a low-volume road project using U-TCP was built. This pavement has a trapezoidal section of 11 cm (4.3 in) in the center of the section and 9 cm (3.5 in) on the edge. The concrete used was 40 MPa with fiber, a residual strength of 1 MPa, according to ASTM 1609-07. The existing road was granular material. Cost of this solution was 3% less than an asphalt surface treatment (including the base material).
Five years after it was built, no distresses can be observed. As shown during several technical visits and in the VIDEO, there is no fatigue cracking, settlement, or lateral displacement of the pavement: https://www.youtube.com/watch?v=3JEQRtej0BM.
Torres del Paine-Acceso Sarmiento: This project was built in 2018 in the National Park “Torres del Paine” where it snows a large part of the year in the south of Chile. The pavement is 8 cm (3.1 in) thick and it was placed directly over the existent granular road.
A recent technical visit showed that the pavement is in perfect conditions as seen in the VIDEO: https://www.youtube.com/watch?v=O8VlP9NnHsY.
Register for the Next ISCP/ACPA Webinar in Series on FRC!!
“Fiber-Reinforced Concrete Pavements” to be Held
May 30, 2019:
https://www.concretepavements.org/2019/04/29/register-for-the-next-iscp-acpa-webinar-in-series-to-be-held-%E2%80%A8may-30-2019-fiber-reinforced-concrete-pavements/