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WORLD BANK. TCP Design (THIN CONCRETE PAVEMENTS) Juan Pablo Covarrubias Washington 2008. Type of Pavement we are Talking About. PERFORMANCE OF CONCRETE PAVEMENTS. The basic performance principles of Concrete Pavements
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WORLD BANK TCP Design (THIN CONCRETE PAVEMENTS) Juan Pablo Covarrubias Washington 2008
PERFORMANCE OF CONCRETE PAVEMENTS The basic performance principles of Concrete Pavements In Chile, the slabs are always curled with the edges lifted up, day and night.
EFFECT OF SUBGRADE STIFFNESS Armaghani 1993
EFFECT OF SUBGRADE STIFFNESS cantilever Granular CBR 40 cantilever CTB Not bonded (polyethylene)
EFFECT OF SLAB LENGTH cantilever cantilever 1/3 L 1/4 L Length 4,5 m. cantilever = 1,13 m cantilever cantilever 1/3 L 1/4 L Length 1,8 m. Cantilever = 0,45 m
SLAB LENGTH AND CURLING 3,8 m 4,5 m Holland 2002
EFFECT OF TIE BARS ON CRACKING OF SLABS Cracking Hiller and Springenschmid, 2004
Development of the Designby TCPavements Research at the University of Illinois Generate Design Method. Coordinate tests at international level
Dx Dx L L Loads of Trucks on Slabs • Minimum Requirement for TCP design: • Maximum slab length less than L • Maximum slab width less than Dx (1/2 lane)
Efect of Loads and Slab Geometry on Stresses Top 2.47 Mpa Bottom 0.20 MPa Top 0.52 Mpa Bottom 0.24 MPa
Project in GuatemalaSlabs 4,5 m x 3,5 m x 24 cm Position I Position II Position III Position IV
Project in Guatemala Slabs 1,8 m x 2,1 m x 15 cm Posición I Posición II Posición III
Summary Guatemala Project Thin slabs with 30 cm widening
FINITE ELEMENTS ANALISIS Equitensional Curves 450 425 400 375 350 325 300 20 Kg/cm2 275 25 Kg/cm2 Length of slab (cm) 250 30 Kg/cm2 225 200 35 Kg/cm2 175 40 Kg/cm2 150 125 100 75 50 25 0 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Thickness (cm)
Thicknesses for Same Stresses and Slab Length Slab length change from 4,5 to 1,75 m 20 y = 0,5431x + 2,0129 18 2 R = 0,9954 16 14 12 10 Slabs 1,75 m 8 6 4 2 0 0 5 10 15 20 25 30 35 Slabs 4,5 m cm cm
CHARACTERISTICS of TCP Design Small slabs (1,8 by 2.4 meters) Granular base (fines < 6%) 15 cm thick Impermeable layer between the sub grade and sub base, if needed Thin joint cut (2 mm thick) No joints sealing No dowel bars or tie bars Lateral confinement with curb, shoulder or vertical steel pins Widened outer lane (30 cm)
Design Design method being used: Design with AASHTO with normal slab size (4.5 m long) Determine by finite elements the stresses within the concrete of the slab for the AASHTO design Calculate slab thickness by iteration with ISLAB2000 with the new configuration of slab size and wheel positions (one set of wheels on each slab) to obtain the same stresses than the AASHTO design. The result, by using this new design approach, is a thinner concrete pavement with the same stresses as AASHTO design
Long Term Costs: NPV (%) Asphalt Traditional Concrete TCP Time (years) 15 20
Guatemala • BM3 Acceso CA9 Sur (Puente Villalobos) • Description • Start Year: end 2005 • Length: 1.68km • 120.000.000 Esals • 15 years design • Ciudad de Guatemala, Guatemala • Highway • Pavement structure • 21 cm thick • Granular base and asphalt base • 14.40m to 21.60m Witdh
Guatemala • Ruta CA-01 Occidente Ciudad San Cristobal - San Lucas (Road to Antigua) • Description • Year 2006 • Length: 11.07km • 80.000.000 Esals • Ciudad de Guatemala – Sacatepéquez, Guatemala • Highway • Pavement Structure • 17cm thick • Granular base and asphalt base • 14.40m Witdh