Knowledge Center
According to an NRMCA study, compressive strength is significantly lost when cylinders are not stored in accordance with ASTM. To summarize, according to ASTM and ACI, if the first 24 to 48 hours of field curing are incorrect, the resulting compressive strength is invalid.
Because it is critical to take all necessary precautions, Gotham Ready Mix would like to extend a gesture of goodwill to our loyal customers by purchasing the correct ASTM-approved curing boxes at our expense.
While our quality control team is working hard to create an appropriate environment for producing high-quality concrete, it is physically impossible to address issues on all projects. Therefore, we are asking everyone to start paying more attention to the quality of testing performed on the job site by independent testing laboratories.
Please read the attached guidance to ensure the correct procedures:
Gotham Ready Mix’s Quality Assurance Guide
Several factors contribute to the difficulty of placing hot weather concrete. They include, but are not limited to, the following:
(i) Consistently warm, hot, and humid days create an environment in which the concrete temperature reaches 90°F during batching.
(ii) Both fine and coarse aggregates are stored outside, accumulating heat from the sun.
(iii) City water temperatures reach 75°F, making cooling the “steaming” aggregates nearly impossible.
(iv) During the day, the barrels on the trucks absorb heat, contributing to the rising concrete temperature while the concrete is in transit.
Needless to say, unless certain precautions are taken, the concrete is likely to reach temperatures higher than those permitted by ACI, causing the concrete to set prematurely. It is critical to take all necessary precautions when testing and inspecting the concrete being delivered to ensure that it meets the requirements set by ASTM, ACI, and NYC Building Code standards.
Accurate information, such as slump, concrete and ambient temperatures, and the age of fresh concrete, are critical to good concrete placement during hot weather and subsequent results as reported by testing laboratories hired by the project’s owners.
Gotham Ready Mix has invested in cutting-edge technology known as “Smarthatch.” This technology aids in concrete quality assurance by providing real-time data on air content in wet concrete and more.
Several trucks in our fleet have such electronic monitoring systems (manufactured by Cidra), and our personnel can monitor fresh concrete features such as concrete temperatures, air content, and slump, to name a few.
Just as it is critical to have fresh concrete data recorded and reported correctly, it is even more critical to have concrete testing cylinders stored in ASTM-approved curing boxes where temperature and moisture are strictly controlled. Everyone involved in concrete placement and quality assurance should be aware of accurate concrete sampling procedures and field sample storage.
Because it is critical to take all necessary precautions, Gotham Ready Mix would like to extend a gesture of goodwill to our loyal customers by purchasing the correct ASTM-approved curing boxes at our expense.
While our quality control team is working hard to create an appropriate environment for producing high-quality concrete, it is physically impossible to address issues on all projects. Therefore, we are asking everyone to start paying more attention to the quality of testing performed on the job site by independent testing laboratories.
Please read the attached guidance to ensure the correct procedures:
