Checking standards for assessing the quality of concrete before putting concrete into the works, the construction team supervises and inspects the quality of concrete at the construction site. As a material used in most construction items, concrete and quality determine the safety and longevity of the building.
When it comes to concrete, it is about compressive capacity. The sample used to measure the strength is a concrete cube with dimensions of 15x15x15cm. Cured under standard conditions specified in TCVN 3105:1993 during 3 days, 7 days and 28 days after the concrete has set. Then it is put into the compressor to measure the compressive force to destroy the sample (thereby determining the compressive strength). Units are in MPa (N/mm2) or daN/cm2 (kG/cm2).
In the concrete construction structure subjected to many different impacts under compression, tensile and shear, in which compression is the most important criterion. Usually, compressive strength is used as a characteristic criterion to evaluate the quality called concrete grade
According to Vietnam construction standards TCVN 4453:1995, concrete structure and reinforced concrete block. Construction and acceptance regulations in Section 7.1.8
The strength of concrete after testing at the age of 28 days by extrusion casting at the site is considered satisfactory when the average value of each sample group (each set includes 3 samples). Not less than the design mark and none of the samples in the samples has strength less than 85% of the design.
Use a core drill to drill samples of concrete components to be tested. Take the mark to process the two ends of the drill bit. Measure the drill sample size. Carefully check the parameters of the diameter and spacing of reinforcement (if any) in each drill sample. Capping drill samples with specialized materials.
Check the parallelism and straightness of the shaft and the 2 capping heads. Classification of drilling samples according to each component of the work item. Take the rake sample to test the concrete strength. Apply the load slowly at a rate between 2:10 daN/cm2 until the specimen is destroyed.
Evaluation of the quality of fresh concrete. Test concrete durability. Searches related to concrete quality. Standards for drilling concrete samples at the site. How to determine the grade of concrete. Check concrete slump. Should fresh concrete be poured. Standard sampling test. Standards for drilling and withdrawing concrete defects. Drilling concrete samples in the field. How to test fresh concrete before putting it and using it at the construction site.
