| Bar
Size |
Cross
Sectional Area |
Nominal
Dia. |
Tensile
Strength |
Tensile
Modulus of Elasticity |
| (mm2) |
(inches) |
(mm2) |
(in2) |
(mm2) |
(in2) |
(MPA) |
(ksi) |
GPA |
psi 106 |
| 6 |
#2 |
38.84 |
0.054 |
6.35 |
0.25 " |
900 |
130 |
40.8 |
5.92 |
| 9 |
#3 |
84.52 |
0.131 |
9.53 |
0.375 " |
900 |
130 |
40.8 |
5.92 |
| 12 |
#4 |
150.321 |
0.233 |
12.70 |
0.50 " |
740 |
110 |
40.8 |
5.92 |
| 16 |
#5 |
220.64 |
0.342 |
15.88 |
0.625 " |
655 |
95 |
40.8 |
5.92 |
| 19 |
#6 |
308.39 |
0.478 |
19.05 |
0.75 " |
655 |
95 |
40.8 |
5.92 |
| 22 |
#7 |
389.67 |
0.604 |
22.23 |
0.875 " |
580 |
85 |
40.8 |
5.92 |
| 25 |
#8 |
562.58 |
0.872 |
25.40 |
1.0 " |
520 |
75 |
40.8 |
5.92 |
| 32 |
#10 |
830.32 |
1.287 |
31.75 |
1.25 " |
480 |
70 |
40.8 |
5.92 |
|
Hughes Brothers reserves
the right to make improvements in the product and/or process
which may result in benefits or changes to some physical-mechanical
characteristics. The data contained herin is considered representative
of current production and is believed to be reliable and to
represent the best available characterization of the product
as of July, 1999.
|
| The cross sectional area of
the rebar is determined by immersing a sample in water
and measuring the volume displacement of piece. When calculating
the cross sectional area, the cross section is assumed
to be a circle. |
|
| Tensile strength is determined as
the average failure minus 3 standard deviations. Tensile
stress varies as diameter increases due to shear lag which
develops between the fibres in the larger sizes. |
|
|
|
The
bond stress to concrete shown is based on pull out
tests performed using the Penn State method. This
method is used as it is easily repeatable and gives
an indication of relative performance.
Forms constructed
out of plywood are used to cast a concrete block
around one meter long rods as shown in this picture.
|
|
In order to control the embedment length within the
block, the rods are prepared with a bond breaker which
consists of soft plastic tubing placed around the rods
to prevent contact between the rod and concrete. The
embedment length is 5 bar diameters.
The concrete used is a high early strength portland
cement, fine aggregate (all purpose sand) and water
(49.89 kg grout, 45.36 kg and, 12.5 I water). The 14
day compressive strength of cylinders is typically 45
MPa.
Previous research has shown that bond strength does
not vary significantly with varying concrete strength,
provided the concrete block is properly sized to prevent
splitting.
Loads are measured by the electronic load cell of a
test frame and the slip between the rod * concrete is
measured by six DC voltage LVDT's, three at each end.
While the free end LVDT's measure direct indication
of free end slip, the loaded end measurements need to
be adjusted for elongation of the rod between the actual
loaded end of the embedment length and the attachment
point of the LVDT's. |
|
|
|
