1. (THIN CONCRETE PAVEMENTS)
WORLD BANK
TCP Design
(THIN CONCRETE PAVEMENTS)
Juan Pablo Covarrubias
Washington
2008 1

2. Type of Pavement we are Talking About

3. 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.

4. DEFORMATION OF A SLAB 15 cm thick, 4 m. long

5. EFFECT OF SUBGRADE STIFFNESS
Armaghani 1993

6. EFFECT OF SUBGRADE STIFFNESS
cantilever
Granular
CBR 40
CTB
Not bonded (polyethylene)

7. EFFECT OF SLAB LENGTH cantilever cantilever 1/4 L 1/3 L cantilever
Length 4,5 m. cantilever = 1,13 m
cantilever
cantilever
1/4 L
1/3 L
Length 1,8 m. Cantilever = 0,45 m

8. EFFECT OF SLAB LENGTH ON SHRINKAGE AND CURLING

9. EFFECT OF SLAB LENGTH ON CURLING
450 cm x350 cm
Thickness= 18 cm
Delta T°=-14 C° Linear
Curling = 2.41 mm
140 cm x175 cm
Curling = 0.49 mm

10. SLAB LENGTH AND CURLING
3,8 m
4,5 m
Holland 2002

11. EFFECT OF TIE BARS ON CRACKING OF SLABS
Hiller and Springenschmid, 2004

12. Development of the Design by TCPavements
Research at the University of Illinois
Generate Design Method.
Coordinate tests at international level

13. Loads of Trucks on SlabsDx L Dx L
Minimum Requirement for TCP design:
Maximum slab length less than L
Maximum slab width less than Dx (1/2 lane)

14. LOADING OF LONG AND SHORT SLABS

15. Efect of Loads and Slab Geometry on Stresses
Top Mpa
Bottom MPa
Top Mpa
Bottom MPa

16. One Axel at the Edge X

17. LOADS AND STRESSES ON A SLAB WHITH ROCKING

18. RELATION: length - thickness - tensile stress

19. EFFECT OF SLAB LENGTH ON CURLING AND OWN WEIGHT STRESSES
450 cm x350 cm
Thickness= 18 cm
Delta T°=-14 C° Linear
Top Tensile stress= 1.40 MPa
140 cm x175 cm
Top Tensile stress= 0.18 MPa

20. Project in Guatemala Slabs 4,5 m x 3,5 m x 24 cm
THICKNESS (cm) 24
SIZE
450x360
Thermal Gradient °C
-14
Elastic Modulus (kg/cm2)
290000
K (kg/cm3) 3
Dowels
YES
Load Position I II
III IV
Tensions (kg/cm2)
21,9
22,5
19,9
10,6
Position III
Position IV
Position I
Position II

21. Project in Guatemala Slabs 1,8 m x 2,1 m x 15 cm
THICKNESS (cm) 15
SIZE
210x180
Thermal Gradient °C
-14
Modulus of Elasticity (kg/cm2)
290000
K (kg/cm3) 3
Load Transfer
LTE 50%
Load Position I II
III
Tensions (kg/cm2)
14,5
20,0
22,1
Posición III
Posición I
Posición II

22. Summary Guatemala Project
Slab Length m.
Thickness cm
Tension
Kg/cm2
Traffic
mESALS
4,5 24
22,5 50
1,8 15
22,1
Thin slabs with 30 cm widening

23. FINITE ELEMENTS ANALISIS
Equitensional Curves 25 50 75
100
125
150
175
200
225
250
275
300
325
350
375
400
425
450 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 26
Thickness (cm)
Length of slab (cm)
20 Kg/cm2
25 Kg/cm2
30 Kg/cm2
35 Kg/cm2
40 Kg/cm2

24. Thicknesses for Same Stresses and Slab Length
Slab length change from 4,5 to 1,75 m
y = 0,5431x + 2,0129 R 2
= 0,9954 4 6 8 10 12 14 16 18 20 5 15 25 30 35
Slabs 4,5 m
Slabs 1,75 m cm cm

25. LOAD POSITION AND SLAB SIZE

26. Top and Bottom Stresses for Length and Thickness

28. 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)

29. 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

30. Construccion Cost TCP H° Tradicional Asfalto EE Diseño Espesor
TCP
H° Tradicional
Asfalto
EE Diseño
Espesor
Costo Km-Pista
H°-TCP
% Ahorro
Asf-TCP
50,000
8cm
$ ,041 -
5cm
$ ,808
$ 2,767 4%
100,000
$ ,000
7cm
$ ,000
$ 11,000
13%
1,250,000
10cm
$ ,715
15cm
$ ,400
$ 31,685
28%
9cm
$ ,803
$ 20,089
20%
3,000,000
12cm
$ ,389
18cm
$ ,411
$ 38,022
29%
$ ,165
$ 21,776
19%
15,000,000
22cm
$ ,000
$ 46,600
13cm
$ ,389
$ 23,989
17%
68,000,000
28 cm
$ ,782
$ 63,371
32%
$ ,889
$ 54,478
160,000,000
22 cm
$ ,759
30 cm
$ ,456
$ 50,696
24%
$ ,885
$ 59,126
27%
*Prices from Chile

31. Long Term Costs: 15 20 TCP NPV (%) Asphalt Traditional Concrete
Time (years) 15 20
Asphalt
Traditional
Concrete
TCP

32. Research at U. de Illinois

33. Sub Grade CBR 3%

34. Geotextile and Granular Base

35. Granular Base less 6% Fines

36. Concrete Slabs finished

37. ATLAS Machine

38. ATLAS Machine

39. Experiences

40. Constructed Projects

41. Guatemala BM3 Acceso CA9 Sur (Puente Villalobos) Description
Start Year: end 2005
Length: 1.68km
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

45. Guatemala
Ruta CA-01 Occidente Ciudad San Cristobal - San Lucas (Road to Antigua)
Description
Year 2006
Length: 11.07km
Esals
Ciudad de Guatemala – Sacatepéquez, Guatemala
Highway
Pavement Structure
17cm thick
Granular base and asphalt base
14.40m Witdh

50. Configuration of Sugar Cane Vehícle (VCMEM)

51. Tensions with Sugar Cane Vehicle (VCMEM)
THICKNESS (cm) 18
Slab size
180x210
Thermal Gradient °C
-21
-14
Position of Load I II
III IV
Tensions (kg/cm2) - K = 3 kg/cm3
25,1
25,4
21,9
21,7
24,4
24,7
21,3 21
23,1
23,4
20,1
19,8
Tensions (kg/cm2) - K = 9 kg/cm3
25,7
26,2
22,6
22,2
24,1
24,5
21,1
20,8
20,6
17,9
17,5
THICKNESS (cm) 22
Slab size
180x210
Thermal gradient °C
-21
-14
Position of load I II
III IV
Tensions (kg/cm2) - K = 3 kg/cm3
16,9
17,1
14,8
14,7
16,5
16,7
14,5
14,3
15,8
16,0
13,8
13,7
Tensions (kg/cm2) - K = 9 kg/cm3
17,9
18,2
15,7
15,5
17,2
14,6
15,1
13,0
12,7

52. Conclution TCP design allows for:
Reduction in thickness, reducing construction costs and keeping the normal performance as traditional design
Increase of axel loads, reducing transportation costs, congestion and contamination.

53. THANK YOU