General overview: for concrete testing
Sampling and testing of concrete is a common step in the production process, samples are taken during production and required tests are carried out on the samples.
The product being manufactured during the testing will then be accepted or rejected based on the test results of the sample. Every rejected product, costs companies a considerable amount of money in materials and labour, it is important that samples are taken by trained Technicians who fully understand the importance of the final decisions that are based on the results complied from each sample.
The type and frequency of testing are generally outlined by the engineer in charge of the job specifications.
Proper sampling methods are required to obtain representative test results on the fresh concrete.
It is important when making test cylinders, to use a non-absorbent material ( metal cylinder ). With a smooth surface, coated with a basic mould oil lubricant to ensure that the material doesn’t stick to the mould. Using utensils such as a compaction rod at a specified length. A rubber mallet. Scoop. Trowel. Collar.
Principle procedure for standardised slump testing is filling a slump cone with fresh concrete in layers, rodding each layer and then removing the support given to the concrete by the slump cone. The vertical subsidence of the concrete that occurs when the slump cone is raised, is termed “the slump” of the concrete.
Compressive Strength Tests
One of the most important properties of concrete is its compressive strength. Testing for compressive strength helps determine whether a product meets specified strength requirements. The objective of compressive strength testing of concrete cylinders is to determine the amount of force it takes to break a cylinder of concrete. The compressive strength is calculated based on the applied load and size of the test cylinder.
Testing provides information to evaluate and adjust mix designs, including the quality of raw materials used in the concrete mixes.