Environmental Engineering Reference
In-Depth Information
procedure to characterize the flexure strength test. In this test, dimensions of
specimens have to be: square section (edge b) and length l = 4b.
Wittmann and Prim [WIT 83] set up an original device for determining flexural
constraint. This method has occasionally been used to evaluate the efficiency of
consolidating treatment on stone samples collected at different depths [SAT 88].
10.1.3.5
. Pulling-off test
RILEM proposes a pulling-off test (n°III.3) not very different from the test of
direct traction (n°III.4). This test is not adapted to characterize a kind of alteration. If
the procedure shows very few differences, in both cases, the traction strength of the
material is tested.
A similar test can be found in French norms: NF B 10-514, “Products of quarry,
limestones, strength of fixings test” [AFN 81b].
10.1.3.6
. Dynamic elastic properties
These properties control the appearance of cracks that can be linked to alteration
due to icing, (see, for example, section 8.3.1). This method is non-destructive and
well adapted to homogenous isotropic materials overall. According to the type of
equipment we use, three different parameters are measured:
- dynamic elasticity modulus
E
[AFN 75b];
- Young's modulus
E
f
by means of a flexure solicitation;
- shearing module
G
thanks to torsion solicitation.
Poisson coefficient
v
can then be calculated using the formula:
V= Eµ
/
2G
−1
[10.1]
The n°III.1 test (“Calculation of the dynamic elasticity modulus by the frequency
of resonance”) proposed by RILEM should be carried out on a minimum of three
specimens. The test gives the dynamic elasticity modulus. Using another method,
test n°III.2 (“Calculation of the dynamic elasticity modulus by the ultrasonic
velocity”) enables us to obtain the same information.
10.1.3.7.
Surface mechanical tests
Two current tests that allow us to characterize a superficial alteration are: those
of the French norm: NF B 10-506, “Products of quarries, limestones - measurement
of the superficial hardness” [AFN 73b]; and those of RILEM test n°IV.1
“Measurement of superficial hardness by scratching wideness”. These simple
