Tests of Concrete Strength across the Thickness of Industrial Floor Using the Ultrasonic Method with Exponential Spot Heads

Abstract

The accepted methods for testing concrete are not favorable for determining its heterogeneity. The interpretation of the compressive strength result as a product of destructive force and cross-section area is burdened with significant understatements. It is assumed erroneously that this is the lowest value of strength at the height of the tested sample. The top layer of concrete floors often crumble, and the strength tested using sclerometric methods does not confirm the concrete class determined using control samples. That is why it is important to test the distribution of compressive strength in a cross-section of concrete industrial floors with special attention to surface top layers. In this study, we present strength tests of borehole material taken from industrial floors using the ultrasonic method with exponential spot heads with a contact surface area of 0.8 mm2 and a frequency of 40 kHz. The presented research project anticipated the determination of strength for samples in various cross-sections at the height of elements and destructive strength in the strength testing machine. It was confirmed that for standard and big borehole samples, it is not possible to test the strength of concrete in the top layer of the floor by destructive methods. This can be done using the ultrasonic method. After the analysis, certain types of distributions of strength across concrete floor thickness were chosen from the completed research program. The gradient and anti-gradient of strength were proposed as the new parameters for the evaluation of floor concrete quality.

A 3D Structural Interactome to Explore the Impact of Evolutionary Divergence, Population Variation, and Small-molecule Drugs on SARS-CoV-2-Human Protein-Protein Interactions

“…Using a mutation scanning pipeline in PyRosetta 59,60 we predicted the impact on binding affinity for each variant (Fig 1.d). The three population variants predicted to have the largest impact on S-ACE2 binding affinity-ACE2_E37K (ΔΔG=1.50), ACE2_M82I (ΔΔG=2.95), and ACE2_G326E (ΔΔG=5.74)-were all consistent with previous experimental screens which identified them as putative protective variants exhibiting decreased binding of ACE2 to S 61,62 .…”

Changes in the Compressive Strength of Concrete in Thin Horizontally Formed Slabs

“…The purpose of the completed research project was to verify previous test results [ 8 ] indicate a lack of variability in the compressive strength of concrete on the thickness of tested elements. The results in the publication [ 8 ] debunked the results of previous studies [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ], in which it was proven that the differentiation of the compressive strength of concrete occurs on the thickness of horizontally formed slabs.…”

“…In studies [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ], it was proven that the differentiation of the compressive strength of concrete occurs across the thickness of thin horizontally formed slabs. The opinions of various researchers concern the size of the difference in the compressive strength between the various levels at which it is tested.…”

The Effect of Steel and Polypropylene Fibers on the Properties of Horizontally Formed Concrete

“…This results in the low compressive strength of the concrete in the upper part of its cross-section (about 30–40% of the designed strength of concrete). According to research [ 2 ], the heterogeneity of concrete also causes the delamination and loosening of its top layer, which contributes to its damage. Fibers can improve the homogeneity of the concrete.…”