IMPROVEMENT OF MECHANICAL PROPERTIES OF RIGID PAVEMENTS full report
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
project report tiger
Active In SP
**

Posts: 1,062
Joined: Feb 2010
#1
08-02-2010, 06:38 AM


IMPROVEMENT OF MECHANICAL PROPERTIES OF RIGID PAVEMENTS

.pptx   IMPROVEMENT OF MECHANICAL PROPERTIES OF RIGID PAVEMENTS.pptx (Size: 1.02 MB / Downloads: 261)
INTRODUCTION

Transportation-basic infrastructure-development

Rigid and flexible

Basic neccesity-stable against loads

Rigid offers more strength “load

But change in temp. “warping up and warping down

To relieve stress-joint

Joint from the weaker plane and most of defects occur there

Increase the mechanical properties such as load carrying capacity and cracking resistance

Methods for improvement



Rigid Pavement

Consist of subgrade, (base course) and Cement concrete slab

It resists minor deformations

Got more strength and life than flexible pavements




JPCP


most common type

control cracks by dividing pavement into individual slabs seperated by contraction joints

3.7m wide and 6.1m long
Use of dowel bar



JRCP

Control cracks by dividing pavement into individual slabs seperated by contraction joints but longer than JPCP
Uses reinforcing steel


CRCP


Does not require any contraction joints

Use reinforcing steel for crack control


JOINTS IN RIGIDPAVEMENTS

TRANSEVERSE JOINTS
Expansion joints
Contraction joints
Warping joints
Construction joints



EXPANSION JOINTS

Provided to allow for the expansion of the slabs

Also permit the contraction of slabs

Provide at interval of 50-60m in winter and 90-120m in summer

In rough interface spacing-140m

The approximate gap width of joints 20-25mm


CONTRACTION JOINTS


Provided to permit the contraction of the slabs


Load transference at the joint is provided through the physical interlocking by aggregates project and implimentationing out at the joint faces


Max.Spacing for unreinforced concrete slab-4.5m and for reinforced concrete slab of thick-20cm-14m


LONGITUDINAL JOINTS

Provide in cement concrete roads


Provide to prevent the longitudinal cracking


Act as hinge to maintain the two slabs together-at the same level



WARPING CRACKS

If joints are not well designed-accommodate warping of slabs at edges - results “ development of excessive stresses and cracking at the edges in an irregular pattern

No structural defect due to the warping cracks if proper reinforcement is provided at the longitudinal & transverse joint as it take care the structural adequacy


BLOWUP/BUCKLING

Occur in hot weather
At a transverse crack or joint
Insufficient width
Caused by infiltration of incompressible material into the joint space
A localized upward movement of the slab edges(buckling) or shattering will occur in the vicinity of the joint


DOWEL BARS

Short mild steel bars
Provides mechanical connection between slabs without resisting horizontal joint movement
Half length is bounded in one cement concrete slab and remaining in other.
Keep free for the movement during expansion and contraction of the slabs
32 -38 mm diameter, 460 mm long and spaced 305 mm apart


REINFORCING STEEL

Used to provide load transfer
Transverse and Contraction joints are often omitted
Since there are no joints the PCC cracks on its own and the reinforcing steel provides load transfer across these cracks
Unlike Dowel Bars- it is bounded to the PCC on either side of the crack in order to hold the crack tightly together


TIE BAR

It is used across the longitudinal joint of cement concrete pavement
It ensure two adjacent slab to remain firmly together
These are not designed to act as load transfer device
Max. tensile force equal to the force required to over come frictional force between the bottom of the adjoining pavement slab and the soil sub grade
Force is considered from joint location to the subsequent joint or free edge



AGGREGATE SELECTION

Research was conducted-three different aggregate types of lime stone, river gravel and trap rock and two different sizes of 25mm and 38mm
Fracture energy represents the cracking resistance, Power Spectral Area Parameter(PSAP)
represents concrete surface roughness and indicates its ability to transfer load across a cra


USES OF FIBERS IN CONCRETE PAVEMENTS

Fibers added in sufficient volume to plain concrete improve properties, fracture toughness and crack width control


Fiber used improve cracking performance of concrete pavements, reduce required slab thickness and increase the allowable joint spacing


CONCLUSION

Concrete pavements are preferred now a days due to its durability and good riding surface.
Inorder to improve the load transfer capacity several methods can be adopted. Conclusion drawn from present study are:
Load transfer across transverse joint can be carried out through dowel bars .
Tie bars help to hold the adjacent slabs together in the case of longitudinal joint.
Reply

Important Note..!

If you are not satisfied with above reply ,..Please

ASK HERE

So that we will collect data for you and will made reply to the request....OR try below "QUICK REPLY" box to add a reply to this page

Quick Reply
Message
Type your reply to this message here.


Image Verification
Please enter the text contained within the image into the text box below it. This process is used to prevent automated spam bots.
Image Verification
(case insensitive)

Possibly Related Threads...
Thread Author Replies Views Last Post
  construction waste recycling full report project report tiger 3 5,646 21-03-2015, 07:15 PM
Last Post: Guest
  intelligent transportation systems full report project report tiger 13 24,076 20-01-2015, 01:31 PM
Last Post: WalterqFole
  FULL REPORT ON ADMIXTURES seminar projects maker 0 1,128 14-09-2013, 02:19 PM
Last Post: seminar projects maker
  PROPERTIES OF GEOPOLYMER CONCRETE REPORT study tips 0 1,012 17-08-2013, 04:47 PM
Last Post: study tips
  Strength Properties of Corn Cob Ash Concrete pdf study tips 0 913 31-07-2013, 03:06 PM
Last Post: study tips
  PRACTICAL APPLICATIONS OF GROUND IMPROVEMENT pdf study tips 0 455 25-06-2013, 02:39 PM
Last Post: study tips
  EARTHQUAKE RESISTENT BUILDING CONSTRUCTION FULL REPORT study tips 0 803 13-06-2013, 03:06 PM
Last Post: study tips
  geopolymer concrete full report project report tiger 18 24,193 07-05-2013, 09:42 AM
Last Post: study tips
  Effect of fine aggregate replacement with fly ash on the mechanical properties study tips 0 651 03-05-2013, 02:28 PM
Last Post: study tips
  RAINWATER HARVESTING full report and ppt project topics 22 41,440 21-03-2013, 04:37 PM
Last Post: study tips