Standards for 7-day and 28-day strength test results
We test concrete cylinders for compressive strength. Most specifications that we see require a compressive strength of 3000 psi (20.7 MPa) and testing at 7 and 28 days. What ACI standard stipulates the percent of the specified compressive strength that the cylinder must meet in order to pass the compressive strength test at both the 7- and 28-day ages? A.A Simple Guide to Concrete Cube Testing,The cubes are generally tested at 7 & 28 days unless specific early tests are required, for example to remove a concrete shutter safely prior to 7 days. Usually 1 cube will be tested at 7 days and 2 cubes at 28 days, however this may vary depending of the requirements, check the design first.Standard Test Method for Compressive Strength of,,5.2 This test method is used to determine compressive strength of cylindrical specimens prepared and cured in accordance with Practices C31/C31M, C192/C192M, C617/C617M, C943, C1176/C1176M, C1231/C1231M, and C1435/C1435M, and Test Methods C42/C42M, C873/C873M, and C1604/C1604M.