This document summarizes a civil engineering student project evaluating factors and remedies for bonding between old and new concrete layers. Tests will include slant shear tests and flexural tests to assess bond strength. Molds have been cast and will be tested in 3-4 days. The project will evaluate the effects of surface roughness, epoxy application, and wire mesh on bond strength and the overall strength of an overlay system compared to a monolithic structure.

1. TITLE OF THE PROJECT
EVALVATING DIFFERENT FACTORS AND
REMEDIES FOR BONDING BETWEEN OLD
AND NEW CONCRETE LAYERS
DEPARTMENT OF CIVIL ENGINEERING
UNIVERSITY OF ENGINEERING AND TECHNOLOGY, PESHAWAR.
Final Year Project Presentation
3rd ROUND.

2. Presented by:
SAJJAD AHMAD
Reg# 11PWCIV3499
NOOR ULLAH
Reg# 11PWCIV3521
MUHAMMAD BILAL
Reg# 11PWCIV3554
Supervised by:
PROF. DR. BASHIR ALAM

3. Assessment of bond strength via tests :
 SLANT SHEAR TEST
 FLEXURE TEST

4.  Moulds are casted and ready for testing.
 Test will be conducted in 3-4 days.
SCHEDULE FOR SLANT SHEAR TEST:

5.  Slant Shear Test:
 The slant shear test is one of the most wide spread bond tests.
 The interface is subjected to a stress state of compression
combined with shear.
 Reliable and Consistent method, because it simulates a stress
state close to the actual use and failure mode of concrete.
Fig# Slant Shear Test. Fig# Slant Shear Test.

6.  Potential factors and remedies considered.
1. Surface Roughness.
2. Provision of Binding materials.
3. provision of Wire mesh.
 Mould Specification.
• Steel mould
• Dim: Width 6”
Depth 6”
Length 12”

7.  Surface roughness.
 Provision of Shear keys.
• Shear keys provided by inserting
wooden piece in concrete cast.
At Casting Time.
After Drying

8.  Provision of Wire mesh.
 A wire mesh is provided at interface and bolted in
substrate via studs.
 Studs in the substrate is
via drilling holes.

9. PROJECT SCHEDULE:
FLEXURAL TESTING:

10.  Scope of the test:
• In Increasing the slab thickness by overlaying of new concrete layer
over casted Concrete layer.
• In Increasing the Pavement Thickness by providing Overlay over
substrate.
 Our Objective.
• We will Show that what is the effect of overlay provision over
substrate on the overall strength of member.
• How strength is varied as compared to monolithic member.
• The best remedies to strengthen the member.

11. MOULD DIMENSIONS: TESTING:

12.  Substrate Nominal strength 3’ * 6’:
 Concrete Strength = 4 Ksi
 Steel strength = 60 Ksi
• Flexure strength
• Under ACI Provisions
Min. Reinforcement = .002 b h = 0.036 in2
Max. Reinforcement = 0.0206 b d = 0.37 in2
• Select #3 Area = .11*2 = 0.22 in2 OK

13.  Substrate Nominal strength:
 Nominal Flexural strength
• Mu = 15.7 K-in
 Under One point load test:
• Wu = 4Mu/L = 2.1 kips
• Shear capacity = 1.52 kips
• Applied Shear = 1.05 kips OK

15.  Substrate + Overlay Nominal strength:
 Nominal Flexural strength
• Mu = 42.10 K-in
 Under One point load test:
• Wu = 4Mu/L = 5.6 kips
• Shear capacity = 3.8 kips
• Applied Shear = 2.8 kips OK
 Also Reinforcement is under ACI Provisions.

16.  One sample fully casted to check the strength of unit casting.

17. • Capacity of mixer available at lab. Is up to 180 lbs.
• Design strength of concrete considered is 4000 psi.
• To get 4000 psi, M20 concrete MIX Ratio is 1:1.5:3
• Mould volume = 6’*6’*30’/123= 0.625 ft3
• Volume of 6 moulds = 6*0.626 = 3.75 ft3
• Calculation in Excel sheet as:

18.  Our consideration for remedies.
1. Roughness.
2. Provision of Epoxy.
3. Provision of Wire mesh.