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IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 5
Influence of the type of measuring device in determininging the static modulus of elasticity of concrete
ABNT NBR 5738:2008 [1], following guidelines in code ABNT NBR
5739:2007 [2]. To reduce the influence of specimen humidity, after
24 hours after casting, the specimens were identified and stored in
water tanks for 28 days. After this, the specimens were removed
from the storage tanks and stored at room temperature and humid-
ity. Sulfur capping was used in all specimens.
The specimens were grouped in packages of 10 specimens and
obtain its compressive strength. The objective of testing the same
specimen for compressive strength after the modulus test is to
verify the homogeneity of the concrete and to allow statistical con-
trol. However, these compressive strength results were not used
in Equation 1. The values used were obtained in the compressive
strength tests mentioned earlier.
Specimens were cast and stored according to provisions in code
Table 1 – Properties of additives and additions used in the concrete
Properties
Material
Additive
GLENIUM 51
Additive
Sikament PF 171
Silica Fume Silmix
Main Function:
3rd Generation
Superplasticizer
Polifuncitonal
Additive
Filler
Chemical Basis
Policarboxilate
Sodium
Lignosulfonate
Amorphous Silica
Appearance:
Viscous Liquid
Liquid
Powder
Color:
Beige
Dark brown
Light or dark gray
Density (g/cm³)
1.067 to 1.107
1.13 to 1.17
2.2
pH:
5 to 7
4 to 6
8 to 10
Table 2 – Concrete mix for fc = 30 MPa
Material Proportioning by m³ of concrete
Mix design (1 : 3.78 : 4.23 )
W/C ratio = 0.73
Materials
Conventionally Vibrated Concrete
Quantity per m³
Cement CP V ARI
236 kg
Artificial sand
891 kg
Gravel size 1 (19 mm)
999 kg
Water
172 kg
Polyfuncitonal Additive
1.65 kg (0.7% of cement)
Superplasticizer
0.94 kg (0.4% of cement)
Silica Fume
18.9 kg (as replacement for 8% of
cement in weight)
Fresh
Concrete
Properties:
Consistency
130 mm
Air
2 %