Concrete inFocus - Spring 2013 - (Page 18)
Acceptance Test Reports
for Ready Mixed Concrete
Who Should Get Them?
he process of testing concrete is reasonably well established for quality assurance of ready mixed concrete delivered
to projects. The owner or his representative
hires an independent testing and/or inspection
agency to perform quality assurance functions during the construction of the Work.
Industry standards provide requirements for
• Qualiﬁcation of testing agencies and testing
• Frequency of testing;
• Standardized procedures for obtaining
samples and performing tests;
• Acceptance criteria for fresh and hardened
concrete tests; and
• Referee testing and criteria for tests that
fail to meet the acceptance criteria.
Standards require the concrete supplier to
maintain a quality control plan and to take
steps to respond to situations when test results
are trending towards potential noncompliance. Prior to a project, the supplier is required
to use a complete test record from previous
projects as a basis for establishing their concrete mixture proportions and properties for
new work and to provide this documentation
in a submittal to the engineer of record.
To meet these requirements, it is essential
that the concrete supplier be provided ALL
reports of acceptance tests performed on the
concrete mixtures delivered during the progress of a project. These test reports should be
provided in a timely manner so that proactive
action can be taken to ensure that speciﬁed
requirements for concrete, especially strength,
are not violated. When low-strength problems
occur, considerable time and money is expended
to evaluate the cause and to take corrective
action. It is thereby beneﬁcial to all parties to
minimize the risk of low-strength concrete.
Why is the distribution of test reports an
issue? Some testing agencies do not provide
test reports to concrete suppliers because they
believe these reports should only go to the
entity that contracted with them for the testing services. Some believe that distribution of
test reports to several entities increases their
cost, although this concern should be less of
an issue with the widespread availability of
electronic communication. Some testing agencies only provide failing strength test results
to concrete suppliers to notify them that a
problem exists. Clearly, this is undesirable
because if previous tests were provided and
a trend was observed, the failing test result
could have likely been avoided.
Many concrete producers have established
relationships with local testing agencies to
ensure that test reports of all tests performed
on their concrete are distributed to them.
Figure 1. Monitoring strength test results relative to strength acceptance criteria.
Figure 2. Running average of three consecutive test results relative to the speciﬁed strength.
Table of Contents for the Digital Edition of Concrete inFocus - Spring 2013
A Legacy in Construction
CalPortland Slip Form Success
Fly Ash FAQ
Acceptance Test Reports for Ready Mixed Concrete
First Batch Plant Certifications in Mongolia
Index of Advertisers
Taking It to the Streets
Impact of Specifications on Concrete Quality
Concrete inFocus - Spring 2013