CIP 35 - Testing Compressive Strength of Concrete（CIP 35 -测试混凝土的抗压强度）.pdf

CIP 35 - Testing Compressive Strength of Concrete WHAT is the Compressive Strength of Concrete? Concrete mixtures can be designed to provide a wide range of mechanical and durability properties to meet the design requirements of a structure. The compressive strength of concrete is the most common performance measure used by the engineer in designing buildings and other structures. The compressive strength is measured by breaking cylin- drical concrete specimens in a compression-testing machine. The compressive strength is calculated from the failure load divided by the cross-sectional area resisting the load and reported in units of pound-force per square inch (psi) in US Customary units or megapascals (MPa) in SI units. Con- crete compressive strength requirements can vary from 2500 psi (17 MPa) for residential concrete to 4000 psi (28 MPa) and higher in commercial structures. Higher strengths up to and exceeding 10,000 psi (70 MPa) are specified for certain applications. WHY is Compressive Strength Determined? Compressive strength test results are primarily used to Fractured Test Specimen at Failure determine that the concrete mixture as delivered meets the requirements of the specified strength, ƒ′c, in the job with the strength specification is minimized. To comply with specification. the strength requirements of a job specification both the following acceptance criteria apply: Strength test results from cast cylinders may be used for quality control, acceptance of concrete, or for estimating • The average of 3 consecutive tests should equal or the concrete strength in a structure for the purpose of exceed the specified strength, ƒ´c scheduling constr