1. Forensic Engineering in Malaysia
Assessment of Reinforced Concrete Structure
By
Ir. Dr. SALLEHUDDIN SHAH AYOP
Head of Jamilus Research Centre (JRC),
Faculty of Civil Engineering and Built Environment
Universiti Tun Hussein Onn Malaysia
2. irwan@uthm.edu.my
Structural & Material Engineering,
Composite Material,
Bio-Concrete Engineering
noridah@uthm.edu.my
Structural Engineering, Precast
Structure, IBS System,
Sustainable Construction
haziman@uthm.edu.my
Concrete Technology, Masonry
Engineering, Material Engineering
shahiron@uthm.edu.my
Structural Assessment, Structural
Health Monitoring, NDT Method,
Material Engineering
norwati@uthm.edu.my
Composite Structures, Concrete
Technology, Forensic Engineering,
Steel Structure Design
nryasmin@uthm.edu.my
Sustainable Construction
Management, Waste
Management, Artificial Neural
Network Modelling
abdulhalim@uthm.edu.my
Construction Management,
Forensic Engineering, Structure
and Material in Civil
Engineering
nhaslin@uthm.edu.my
Occupational Safety & Health,
Industrialized Building Systems,
Construction Management
PROF. Ir. Ts. Dr. MOHD IRWAN BIN
JUKI
PROF. Ir. Dr. NORIDAH BINTI
MOHAMAD
PROF. Ir. Ts. Dr. MOHD HAZIMAN BIN
WAN IBRAHIM
PROF. Ir. Ts. Dr. SHAHIRON BIN
SHAHIDAN
PROF. MADYA Ir. Dr. NORWATI BINTI
JAMALUDDIN
PROF. MADYA Ir. Dr. NOOR YASMIN
BINTI ZAINUN
PROF. MADYA Ir. Ts. Dr. ABDUL HALIM
BIN ABDUL GHANI
PROF. MADYA Ir. Ts. Dr. NOR
HASLINDA ABAS
Ir. Dr. SALLEHUDDIN SHAH BIN AYOP
sallehs@uthm.edu.my
Concrete Technology, Marine
Structures, Corrosion Damage,
Forensic Engineering
3. Forensic Work in Civil Engineering
“The investigation of materials, products, structures or
components that fail or do not operate, or function as
intended, causing personal injury or damage to
property”
11. Data Collection
• Non-destructive Test (NDT)
- Rebound Hammer Test (BS EN 12504-2: 2021)
- UPV Test (ASTM C597-22)
- Cover meter
- Half-cell Potential Measurement Test (ASTM C876-15)
- Carbonation Test
- Laser Doppler Vibrometer
- Acoustic Emission (AE)
• Destructive Test
• Tensile Test (MS 146:2014)
• Coring Test (BS EN 12504-1: 2019)
12. Rebound Hammer
• Concrete members to be tested shall be at least 100
mm (4 in) thick and fixed within a structure.
• A test area shall be at least 150 mm (6 in) in
diameter.
• Do not conduct tests directly over reinforcing bars
with cover less than 0.75 in (20 mm).
• Take minimum of nine readings to obtain a reliable
estimate of the rebound number for a test area.
• The result shall be taken as the median of all the
readings, adjusted if necessary to take into account
the orientation of the hammer in accordance with
the manufacturer's instructions and expressed as a
whole number.
• The compressive strength of the concrete can be
calculated from the median rebound value (R)
based on the conversion curve provided by the
manufacturer.
13. UPV Test
- UPV test method covers the measurement of
velocity of ultrasonic pulses in concrete.
- The purpose of pulse measurement is to find a
correlation of pulse velocity and strength as a
measure of concrete quality.
- Table 1: Velocity criteria for concrete quality
grading
Pulse Velocity
(km/second)
Concrete Quality (Grading)
Above 4.5 Excellent
3.5 to 4.5 Good
3.0 to 3.5 Medium
Below 3.0 Doubtful
Ref: Malhotra V. M (Ed), Testing Hardened Concrete: Non-destructive
Methods, ACI
14. Cover meter
• To measure the thickness of the
concrete cover.
• To determine the location &
position of the reinforcing bar
in concrete
• To determine the size of
reinforcing bar in concrete
15. Half-cell Potential Measurement
• Half-cell corrosion detection technique was conducted
to assess the steel condition in the concrete structure.
This technique evaluates the risk of corrosion activity
of steel in concrete. The test was conducted by
referring to ASTM C876-15 using copper-copper
sulphate electrode connected to a voltmeter. The
possible potential electrode values were then
compared with the criterion listed in the Table below.
Open circuit potential
(OPC) value
(mV vs. CSE)
Corrosion condition
< -500 Severe corrosion
< -350 High (< 90% risk of corrosion)
-350 to -200 Intermediate corrosion risk
> -200 Low (10% risk of corrosion)
16. Carbonation Test
• Carbonation is a process in which carbon dioxide
from the atmosphere diffuses through the porous
cover concrete and may reduce the pH to 8 or 9, at
which causes depassivation of protective layer of
the reinforcement bars and initiates their corrosion.
• Carbonation depth is assessed using a solution of
phenolphthalein indicator that appears pink in
contact with alkaline concrete and colourless at
lower levels of pH.
• The test is carried out by spraying the indicator on
freshly exposed surfaces of concrete broken from
the structure or on split cores. Alternatively, the
powder from drill holes can be sprayed.
17. Laser Doppler Vibrometer
• Vibration waves were captured with Laser
Doppler Vibrometer, LDV at a designated
location on the affected floor area.
• From the test results, the peak vibration
acceleration at the location can be determined.
• The peak vibration acceleration for normal
reinforced concrete floors as in previous
studies is 0.007 m/s2 whereas for concrete
masonry load bearing system floor, the peak
vibration acceleration is 0.00042 m/s2
19. Tensile Test
• To determine strength properties of steel
element such as steel bar or steel member.
20. Coring Test
• The ratio of the maximum aggregate size in
the concrete to the diameter of the core has a
significant influence on the measured strength
when it approaches values greater than about
1:3.
• The preferred length diameter/ratios are:
• 2,0 if the strength result is to be compared to cylinder
strength;
• 1,0 if the strength result is to be compared to cube
strength.
• Determine the compressive strength of each
specimen by dividing the maximum load by
the cross-sectional area, calculated from the
average diameter and express the result to the
nearest 0,1 MPa (/mm²).
21. In-Situ Strength Assessment
BS EN 13791: 2019
Assessment of in-situ compressive strength in
structures and precast concrete components
• Clause 8- Estimation of compressive strength for
structural assessment of an existing structure
• Clause 9 Assessment of compressive strength class of
concrete in case of doubt.
• Assessment based on core data or core + NDT data
