e.
If the equivalent average [28][90]-day strength for the lot is
below the Average Flexural Strength Required for Mixtures by 138
kPa 20 psiflexural strength or more, at any time, adjust the
mixture to increase the strength, as approved.
f.
Fabricate and cure two beams for every 1500 cubic meters 2000
cubic yards of concrete placed. Fabricate and cure in accordance
with ASTM C 31/C 31M; test at 14-days of age in accordance with
ASTM C 78.
g.
The Contractor's CQC testing agency shall maintain up-to-date
control charts for strength, showing the 7-day CQC compressive
strength, the 14-day compressive strength (from acceptance tests)
and the [28] [90]-day equivalent flexural strength of each of
these for each lot.
a.
Take samples for strength tests at the paving site. Fabricate and
cure test beams in accordance with ASTM C 31/C 31M; test them in
accordance with ASTM C 78.
b.
Fabricate and cure 2 test beams per sublot from the same batch or
truckload and at the same time acceptance beams are fabricated and
test them for flexural strength at 7-day age.
c.
Average all 8 flexural tests per lot. Convert this average 7-day
flexural strength per lot to equivalent [28] [90]-day flexural
strength using the Correlation Ratio determined during mixture
proportioning studies.
d.
Compare the equivalent [28] [90]-day flexural strength from the
conversion to the Average Flexural Strength Required for Mixtures
from paragraph of same title.
e.
If the equivalent average [28] [90]-day strength for the lot is
below the Average Flexural Strength Required for Mixtures by 490
kPa 69 psi flexural strength or more, at any time, adjust the
mixture to increase the strength, as approved.
f.
The Contractor's CQC testing agency shall maintain up-to-date
control charts for strength, showing the 7-day CQC flexural
strength and the [28] [90]-day flexural strength (from acceptance
tests) of each of these for each lot.
3.12.4
Reports
All results of tests or inspections conducted shall be reported informally
as they are completed and in writing daily. A weekly report shall be
prepared for the updating of control charts covering the entire period from
the start of the construction season through the current week. During
periods of cold-weather protection, reports of pertinent temperatures shall
be made daily. These requirements do not relieve the Contractor of the
obligation to report certain failures immediately as required in preceding
paragraphs. Such reports of failures and the action taken shall be
confirmed in writing in the routine reports. The Contracting Officer has
the right to examine all contractor quality control records.
-- End of Section --
SECTION 02753
Page 77