A simple equipment known as Rebound Hammer or Schmidt Hammer is used for this purpose. Surface hardness measured during the test give an idea about the soundness and quality of cover concrete.
Powers and Functions of CPCB - The Water Act 1974.pdf
Rebound hammer types
1. Rebound Hammer
A simple equipment known as Rebound Hammer or Schmidt
Hammer is used for this purpose. Surface hardness measured
during the test give an idea about the soundness and quality of
cover concrete.
Locations having very low rebound numbers indicate weak
surface concrete and may be affected by corrosion. The quality of
concrete may be interpreted as shown in the above table.
3. Hammer
Concrete Test Hammer, ideally suited for on-site tests of concrete
and is widely used instrument for analyzing the uniformity and
compressive strength characteristics of concrete structures and
Detection of weak spots in the concrete. Rebound values are read
from a scale for subsequent calculation of the mean. Compressive
strength values can be read from a conversion diagram.
4. Digital rebound hammer
Digital test hammers are an advanced, completely automated
system for estimating concrete compressive strength. Its
calculation, memory and recording functions allow for quick,
easy and accurate test results.
Discard values for multiple test results can be set; the mean,
median and compressive strength can also be calculated. The
addition of modern microprocessor technology allows the data to
be stored, printed and transferred to a personal computer for
further analysis, or inclusion in your reports.
5. Hammer
The Schmidt rebound hammer is principally a surface hardness
tester. The Original Schmidt is available in models with different
impact energies, each test hammer designed for a specific test
application.
The Romans were aware of the fact that good mortar (opus
caementicium) is hard and of a high compressive strength. They
tested its quality subjectively by scratching the surface with an
iron nail.
But only in the mid-20th century was this know-how utilized. A
device was invented which made non-destructive compressive
strength testing feasible.
6. hammer
Digital Schmidt rebound hammer is the most advanced
instrument in its category with follows:
The instruments body lies very comfortably in the hand. The
display is highly readable under any conditions.
A two-layer seal prevents dust and dirt from penetrating to the
interior of the instrument.
The forward and the rebound velocity of the hammer mass are
both measured in close proximity to the point of impact. The
rebound value requires no angular correction.
A larger number of measurement points can be easily collected by
the instrument and automatically evaluated according to
statistical criteria.
7. RCPT-Rapid chloride
permeability test
The PROOVE it system is used to evaluate the resistance of concrete to
the ingress of chloride ions in two ways:
By determining how easy it is to force chloride ions into saturated concrete
by applying an electrical potential across a test specimen in accordance
with AASHTO T 277 or ASTM C1202. This is known as the "Coulomb
Test" or the "Rapid Chloride Permeability Test (RCPT)."
By measuring the penetration depth of chloride ions, after an electric
potential has been applied to the specimen in accordance with
NORDTEST BUILD 492 (Chloride Migration Coefficient from Non-
Steady State Migration Experiments) to determine the "Chloride Migration
Coefficient," which can be used to estimate the chloride diffusion
coefficient for service life calculations.
