Faculty of Architecture BDes
Constructing the Environment
Before coming to the laboratory, you should have read through these instructions
and be familiar with the general nature of
the work required.
Record the results as the work proceeds, and write
up on the report sheets
To teach the students how to do and interpret simple compressive loading tests.
To find out the strength of the concrete cylinders mad
e in Experiment 1, and of bricks,
To give the students an idea of the strength of concrete and brick, and some of the
factors that affect their strength.
TESTING CONCRETE CYLINDERS
The equipment to be used is a hydraulic comp
ression machine with a measuring gauge. In
order to obtain consistent test results, the load should be applied at a uniform speed of
about 4kN per second, with the oil pressure being varied as necessary to obtain this speed.
The dial indicates the
that the ram applies to materials being tested. This dial
indicates force in kiloNewtons (kN).
Take the cylinders of concrete made in the first experiment. Measure and note their
mass separately. Identify the concrete mix by the colour of the mould t
he cylinder was
cast in and the water/cement ratio.
The cylinders should be fairly consistent in mass. A lightweight cylinder probably means it
was not fully compacted, and has air voids in it.
Place each of the specimens vertically in the testing machi
ne in turn, and load it to
destruction. Note the batch (red, blue or yellow), and the
mode of failure
in each case.
Operating the press
The valve at the bottom of the oil reservoir and the valve behind the dial gauge should
prior to each test. After each test release the pressure on these valves
Attach the safety screen before loading the test pieces. Sometimes a very
strong specimen will shatter on failure.
Most failures will be gradual.
From the maximum force, calculate the
of each specimen.
To calculate the crushing stress.
Stress is force per unit area. The force is given directly by the gauge, in kN.
The area of concrete on which it acts is the cross
section of the
ecimen. The specimen is
150mm diameter, so the area is πD
/4 = 17671 mm
= P x 10
/ 17671 MPa.,
is the crushing stress, and P is the force in kiloNewtons (so P x 10
is the force in Newtons).
Newtons per mm
is the same as M
egaNewtons per m
Faculty of Architecture
DESA 1102, Design Studies, Structures
RECORD ALL THE RELEVANT INFORMATION ABOUT THE DIFFERENT CONCRETES
AND TESTS ON THE ATTACHED
Before filling out the report, make sure you know all the results of your group’s work. Ask
leagues if necessary.
PART B: TESTING BRICKS AND BRICK PIERS
(a) Crushing tests.
The crushing strength of a brick is tested by laying it flat between the plates of the testing
machine, and loading it at a uniform, slow rate.
this crushing test:
on each of two single bricks, and
on each of t
made piers, each three bricks high.
the maximum crushing force, and observe the mode of failure in each case.
Make sketches showing how the test pieces failed. Compare the results of the bricks
and the “walls”. What can be the reason
for the difference?
the mean crushing strength in megapascals (MPa) in each case.
The crushing strength (compressive strength) is found by dividing the force needed to
cause the brick to fail (P, the maximum force it can resist) by the cross
ctional area (A)
of the brick
with the bearing plate of the machine f
that the size of the face of the bricks in contact with the bearing plate must be
the bricks are tested
Before leaving the laboratory, properl
y clean all the equipment. Place the broken
concrete iand brick in the wheelbarrow and bins provided and deposit it in the
industrial waste bin outside.