Structural strength enhancement of rigid pavement using scrap
1. Structural Strength Enhancement of
Rigid Pavement Using Scrap Steel Fibre
Reinforcement
Presented by:
SASANE KAUSTUBH S(PF34)
2. •The inclusion of fiber in concrete, mortar
and cement paste can enhance many of
the engineering properties of the
matrix, such as fracture
toughness, flexural strength and
resistance to fatigue, impact, thermal
shock and spalling.
•The fibres may act as shear
reinforcement and also improve the
capacity of the bars due to increased
crack distribution
3. The main objectives of this study are:
To investigate the use of steel scraps as a Steel
Fiber Reinforcement in FRC
To study the mechanical characteristics of the
SSFRC
To optimize the fiber proportions
To check the toughness resistance of the SSFRC
To check the abrasive resistance of the SSFRC
To find out the cost effective cross section of the
pavement.
*Scrap Steel Fiber Reinforced Concrete (SSFRC)
4. Chettinad brand Ordinary Portland Cement (OPC) 43
Grade confirming to IS: 4031-1988. Locally available river
sand confirms to Zone II of IS: 383-1970 as fine
aggregate, Crushed granite aggregate of maximum size
20 mm confirming to IS: 383 as coarse aggregate and
Potable water are used. Steel Scraps of length 25 mm to
30 mm, width 1.5 to 2 mm and thickness 0.3 to 0.4 mm
which is obtained from the lathe machines as waste or by
product are used as reinforcing material in the concrete.
Super plasticizer – Conplast SP432 MS supplied by M/S
FOSROC India Private Ltd. Is used to improve the
workability of the concrete. The dosage of super
plasticizer to be added with the concrete is found out from
the slump test conducted in the laboratory.
5. Pavement Design and Analysis
Pavement slab is designed as per IRC 58:2002[8]. The flexural strength is
directly taken from the beam flexural test. The design details are tabulated in
Table 6. The Axle load spectrum is taken from IRC: 58 -2002 and other data
used in this design is given below:
Elastic modulus of concrete = 3 x 10-5 N/mm2
Tyre pressure = 8 kg/cm²
Spacing of contraction joints = 4.5m
Design life = 20 years
Poisson’ ratio = 0.15
Rate of traffic increase = 0.075
Present traffic =1000 cvpd
Elastic Modulus of Sub grade
Reaction of the DLC sub-base = 8 kg/cm³
Coefficient of thermal Expansion of concrete = 10x 10-6 /ºC
From Table 6, it is clear that the addition of small amount of fiber will also
reduce the thickness of the pavement slab. For M30 Concrete thickness saved
in construction with SSFRC is 41%, for M35 concrete thickness saved with
SSFRC is 38% and for M40 concrete thickness saved in SSFRC is 33%.
7. According to Gopalaratnam (1991)[2] for a
given type of fiber, a higher volume fraction
provides more energy absorption capacity or
toughness as long as the fibres can properly
be mixed and the composite can be cast and
compacted properly. This result should be
expected because more fibres provide more
resistance, especially in the tension zone. For
the given fibre geometry, longer fibres
typically provide greater toughness
8. Balasubramanian et al. (1996)Shave
investigated the impact resistance of the
specimens with 0.5%, 1.0%, 1.5%, and 2.0% for
each of the three types of steel fibres using
Schrader’s test Device.
Ravishankar (2006)investigated the mix design
aspects of steel fibre reinforced concrete and
concluded that there is an increase of 42% in
modulus of rupture due to addition of fibres in
plain concrete.
9.
10.
11.
12. From the experimental studies and subsequent pavement
analysis carried out as per IRC: 58-2002, it is concluded
that the compressive strength of SSFRC increased when
compared to plain cement concrete. Addition of steel
scraps increases the flexural strength of SFRC to great
extent.
The mechanical properties of the concrete are increased
by increasing the proportion of the steel scrap up to 1.5%.
From 1.5% to 2.0%, it shows slight decrease in mechanical
strength. At 2.0% of steel proportion, there is considerable
reduction in the mechanical strength of SSFRC. It the
pavement thickness is decreased by 41% and which is
economical when compared to plain cement concrete
slab.
13. U. Ravisankar, H.V. Venkata Krishna and Sures ‘Mix Design Aspects of SFRC
PavementDesign’ Indian Highways (May 2006) Vol.34, No.5 and pp 44-50.
K. Sankar, ‘A Study on the Effect of Fiber Reinforcement in Concrete Pavements,’
M.TechThesis, Department of Civil Engineering, National Institute of
Technology, Tiruchirappalli –620-015.
‘Method of Test for Determining Pavement and Structures’, Department of
Transportation,Engineering Service Centre, Sacramento, California 95819– 4612
(Feb.2000).
IRC-58:2002, ‘Guidelines for the Design of Rigid Pavements.’ Figure 5: Control
Concrete specimens failed under Impact Figure 6: SSFRC specimen failed under
impact
IRC:SP:46-1997, ‘Steel Fibre Reinforced Concrete for Pavements’.
V. S. Gopalaratnam, S. P. Shah, G. B. Batson, M.E. Criswell, V. Ramakrishnan and
M. Wecharatana, ‘Fracture Toughness of Fiber Reinforced Concrete’. ACI Material
Journal, 88 4 (1991), pp. 339–353.
K. Balasubramaniam, B. H.Bharat Kumar, S. Gopalakrishnan and V.S.
Parameswaran, ‘Impact Resistance of Steel Fibre Reinforced Concrete,’ The
Indian Concrete Journal (May, 1996), pp. 257-262.
N. P. Banthia, S. Mindess and A. Bentur, ‘Impact Behavior of Concrete Beams,’
RILEM, Mater.Struct.20(1987) pp. 293- 302
