ture and cured at 20, 5, and 10C
Table 12. Phase II, Task 2; concrete mixture proportions. A Type I
(70, 23, and 14F).
cement with a 365-kg/m3 (611 lb/yd3) cement factor was used.
Table 13 shows the results from
Ingredient
Control
Trial
a reexamination of ARL-506 and
EX-4 in comparison to Pozzutec 20
Water/cement
0.463
0.4380.440
and admixture-free concrete. All
Hugo sand, SG 2.58
24.5 kg (53.9 lb)
25.5 kg (56.2 lb)
mixtures had a cement factor of
365 kg/m3 (611 lb/yd3) and a w/c
Coarse agg, SG 2.84
36.4 kg (80.0 lb)
36.4 kg (80.0 lb)
of 0.48. At 5C (23F), the con-
Trial admixture
none
60 mL/kg (90 fl oz/cwt)
crete made with high dosages of
none
100 mL/kg (150 fl oz/cwt)
ARL-506 and EX-4 gained 15 and
Pozzutec 20
60 mL/kg (90 fl oz/cwt)
none
17%, respectively, more strength
than Pozzutec 20 at 28 days. At
10C (14F), these admixtures produced concrete
The concrete was mixed at room temperature and
cured at 5 and 10C (23 and 14F). The best
that was significantly weaker compared with
admixtures were selected for further testing in
Pozzutec 20 concrete cured at that same tempera-
Phase III. The follow-up tests consisted primarily
ture. At room temperature neither of these two
of reexaminations and confirmation testing of the
trial admixtures provided as much strength as
better results.
that recorded for Pozzutec 20; the high doses of
ARL-506 and EX-4 gained 16 and 5%, respectively,
less strength than Pozzutec 20 at 28 days. Based
Results and discussion
on the room temperature results, the ARL-506
Task 1: Mortar screening
and EX-4 were excluded from further consider-
ation.
There is little to report in this task except to list
Table 14 shows the results of combining pro-
those admixtures that performed relatively well:
pylene glycol and urea, two freeze-point depres-
ARL-506, EX-3, EX-4, EX-5D, EY-1, EY-3, EY-7,
sants not previously examined, with Pozzutec 20.
and EY-10. The results from all mortar screenings
The purpose of doing this was to determine if
are provided in Appendix C. Criteria such as set
simply adding a freeze-point depressant to
time, both initial and final, compressive strength,
Pozzutec 20 would enhance its low-temperature
and admixture dosage were used in picking the
best performances.
Table 13. Strength results from two trial admixtures in concrete
Task 2: Concrete testing
with a 365-kg/m3 (611 lb/yd3) cement factor and a 0.48 w/c.
Three trial admixtures were found
to perform well in concrete. The pri-
Admixture
Curing
mary yardstick for admixture selec-
code name-dosage
temperature
Compressive strength--MPa (psi)
(C)
mL/kg (fl oz/cwt)
7 days
14 days
28 days
tion was compressive strength at
10C (14F). The results from all
Control
20
28.3 (4102)
31.7 (4593)
34.2 (4960)
concrete testings are provided in
EX-4-60 (90)
20
27.2 (3947)
27.6 (4008)
30.1 (4371)
Appendix D. The admixtures cho-
EX-4-100 (150)
20
29.4 (4258)
32.3 (4682)
35.0 (5079)
ARL-506-60 (90)
20
33.4 (4848)
36.0 (5225)
37.8 (5479)
sen for further evaluation were ARL-
ARL-506-100 (150)
20
33.2 (4810)
37.0 (5362)
39.6 (5748)
506, EX-4, and EY-11; ARL-506 is an
Pozzutec 20-100 (150)
20
35.4 (5140)
38.9 (5645)
41.6 (6036)
analog of Pozzutec 20.
Control
5
1.1 (164)
1.2 (180)
1.8 (260)
EX-4-60 (90)
5
9.0 (1306)
11.4 (1649)
12.5 (1815)
Task 3: Follow-up testing
EX-4-100 (150)
5
12.4 (1797)
16.2 (2348)
19.0 (2761)
Task 3 further examined the three
ARL-506-60 (90)
5
8.3 (1202)
11.8 (1707)
13.7 (1985)
best trial admixtures from Task 2. It
ARL-506-100 (150)
5
8.6 (1254)
13.5 (1964)
18.7 (2716)
also examined two other groupings
Pozzutec 20-100 (150)
5
8.4 (1211)
12.1 (1752)
16.2 (2349)
of admixtures: two freeze-point de-
Control
10
0.0 (0.0)
0.0 (0.0)
0.0 (0.0)
pressants in combination with Poz-
EX-4-60 (90)
10
3.4 (492)
3.4 (496)
3.9 (570)
zutec 20, and three new trial admix-
EX-4-100 (150)
10
3.3 (482)
5.1 (738)
7.0 (1012)
tures. The results are presented in
ARL-506-60 (90)
10
1.8 (259)
2.2 (312)
2.8 (410)
ARL-506-100 (150)
10
1.4 (203)
2.9 (414)
4.2 (610)
Tables 1316. In all cases, the con-
Pozzutec 20-100 (150)
10
4.4 (645)
5.5 (799)
8.6 (1243)
crete was mixed at room tempera-
12
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