Civil Engineering Reference
In-Depth Information
should be noted that the boiling procedure in ASTM C 642
can render the specimens useless for certain additional
tests, especially strength tests. The density can be obtained
by multiplying the relative density (specific gravity) by
the density of water (1000 kg/m
3
or 62.4 lb/ft
3
).
Saturated, surface-dry density (SSD) is often required
for specimens to be used in other tests. In this case, the
density can be determined by soaking the specimen in
water for 48 hours and then determining its weight in air
(when SSD) and immersed in water. The SSD density is
then calculated as follows:
M
MM
1
D
=
SSD
Fig. 16-17. View of concrete air-void system under a micro-
scope. (67840)
1
2
where
D
SSD
is density in the SSD condition
M
1
is the SSD mass in air, kg (lb)
lineal distance (Fig. 16-17). See
Chapter 8
“Air-Entrained
Concrete,” for more information.
M
2
is the apparent mass immersed in water, kg (lb)
is the density of water, 1000 kg/m
3
(62.4 lb/ft
3
)
Density, Relative Density (Specific
Gravity), Absorption, and Voids
The density, relative density (specific gravity), absorption,
and voids content of hardened concrete can be determined
in accordance with ASTM C 642 procedures (Table 16-2). It
The SSD density provides a close indication of the
freshly mixed density of concrete. The density of hard-
ened concrete can also be determined by nuclear methods
(ASTM C 1040 or AASHTO T 271).
Table 16-2. Permeability and Absorption of Concretes Moist Cured 7 Days and Tested After 90 Days.
Permeability
Absorption
Compressive
Vol. of
Absorption
after im-
Cement,
strength at
90 days
Por-
permeable
after im-
mersion
kg/m
3
Mix
90 days,
RCPT,
ponding,
Water,
Air,
osity,
voids,
mersion,
and
(lb/yd
3
)
No.
w/cm
MPa (psi)
coulombs
% Cl
m/s**
m/s**
%
†
%
%
boiling, %
ASTM
ASTM
C 39
C 1202
(AASHTO
(AASHTO
AASHTO
API
API
ASTM
ASTM
ASTM
T 22)
T 277)
T 259
RP 27
RP 27
C 642
C 642
C 642
445
104.1
2.81 x 10
-10
1
0.26*
65
0.013
—
7.5
6.2
2.43
2.56
(750)
(15100)
445
76.7
3.19 x 10
-10
2
0.29*
852
0.022
—
8.8
8.0
3.13
3.27
(750)
(11130)
381
46.1
2.61 x 10
-13
1.16 x 10
-9
3
0.40*
3242
0.058
11.3
12.2
4.96
5.19
(642)
(6690)
327
38.2
1.94 x 10
-12
1.65 x 10
-9
4
0.50
4315
0.076
12.5
12.7
5.45
5.56
(550)
(5540)
297
39.0
2.23 x 10
-12
1.45 x 10
-9
5
0.60
4526
0.077
12.7
12.5
5.37
5.49
(500)
(5660)
245
28.4
8.32 x 10
-12
1.45 x 10
-9
6
0.75
5915
0.085
13.0
13.3
5.81
5.90
(413)
(4120)
* Admixtures: 59.4 kg/m
3
(100 lb/yd
3
) silica fume and 25.4 ml/kg of cement (30 fl.oz/cwt) HRWR (Mix 1); 13.0 ml/kg (20 fl.oz/cwt) HRWR
(Mix 2); 2.2 ml/kg (3.4 fl. oz/cwt) WR (Mix 3).
** To convert from m/s to Darcy, multiply by 1.03 x 10
5
, from m/s to m
2
, multiply by 1.02 x 10
-7
.
† Measured with helium porosimetrie.
Adapted from
Whiting (1988)
.
