The good, the bad, and the ugly
Sampling may be part of a forensic investigation. As we’ve discussed in previous blogs, it isn’t practical to obtain enough concrete cores for a proper statistical representation. Most owners don’t […]
Testing
Diagnosing ASR
Alkali-silica reaction is a common deterioration mechanism in concrete. Some silicate minerals in aggregates react with hydroxide ions in concrete pore water, forming a gel that imbibes water and swells. […]
What engineers should know about acceptance testing
At the ACI spring convention, the Hot Topic session focused on acceptance testing of concrete. Someone pointed out that we’ve been having the same discussion for the last 40 years. […]
Concrete acceptance testing
Concrete acceptance testing refers to the testing of concrete sampled directly from the ready mixed concrete truck. Its purpose is to verify the compressive strength of the material as delivered […]
Concreting in hot weather
Unlike most materials, concrete is often cast and cured on site rather than in the (more) controlled conditions of a factory. That means that temperature and humidity—as well as exposure […]
Concrete cube tests
In previous blogs we’ve discussed various aspects of acceptance testing of concrete. The standard concrete compressive strength specimen in North America is a cylinder, either 6 x 12 inches or 4 x 8 inches. In most […]
How to evaluate concrete core strengths
There are many reasons to take cores of in-place concrete. You might want to know the capacities of the footings and columns in an old building you plan to adapt […]
ACI PRC-132.1 assigns responsibilities in caring for concrete test specimens
ACI PRC-132.1-22, “Responsibility for the Care of Test Specimens for Acceptance of Concrete“, describes who should do what to ensure accurate acceptance testing. As a TechNote rather than a standard […]
ASTM C1077
ASTM C1077 is the “Standard Practice for Agencies Testing Concrete and Concrete Aggregates for Use in Construction and Criteria for Testing Agency Evaluation.” Agencies such as AASHTO provide independent accreditation […]
Prescription to performance
As part of its Prescription to Performance (P2P) initiative, the National Ready Mixed Concrete Association surveyed its members. They wanted to know which prescriptive requirements kept them from optimizing concrete. […]