A Study to Establish Correlation Between Rebound Value and Compressive Strength of Concrete Using Materials Available Locally in Nagpur

This study has been taken to investigate the exact rebound-strength relationship of different grades of concrete, as the curves generated for traditional hammers are outdated. Using the material available in the Nagpur region, cube specimens were cast and tested as per IS:516-1959 [1]. Several sets were cast with varying cement contents, decided by mix design, to give a strength range of 10 to 50 Mpa. However, for this study, the Target Mean Strength Standard Deviation factor is not considered. We tested these sets for compressive strengths; each specimen was checked for rebound value for compressive Strength, each specimen was checked for rebound value on four faces. Thus, for each specimen, data for rebound value and Compressive Strength is available. Using this data, a curve for Compressive Strength and rebound value was plotted. The curve generated indicated that the strengths obtained for the same rebound value are higher than that using the traditional curve. There is an increase of about 47% up to a strength of 21 Mpa. From 21 to 38 Mpa, this increase is almost constant to about 30%. From this point forward, the rate of increased Strength reduces by 25% and 14% at 40 Mpa and 45 Mpa, respectively.

The thickness of the ventricles and interventricular septum in males with overweight according to echocardiography

Introduction. Mortality from cardiovascular disease ranks first in the world. New and high requirements are required for the anatomical substantiation of emerging methods and methods of treatment. In modern literature, there are many publications on the issues of heart morphology, but data on the influence of gender, age, body weight on heart parameters are insufficient, fragmentary and often contradictory.Objective. To determine the thickness of the ventricles and interventricular septum in overweight men when performing echocardiography and to assess the presence or absence of the relationship of these parameters with age and body mass index (BMI) of the subjects. Patients and methods. The analysis of the protocols of ultrasound examination of the heart of 68 apparently healthy men of adolescence, the first and second periods of adulthood with a body mass index of 25.0–29.9 kg/m², with no pulmonary and cardiac pathology and the risk of cardiovascular diseases was carried out. Ultrasound examination was performed on an Aloka ProSound Alpha 6 ultrasound scanner. Results and discussion. When comparing the mean values of heart parameters in overweight men in three age groups according to the Kruskell – Wallis criterion, no statistically significant differences were found between the mean values (p > 0.05). Revealed a moderate strength relationship between the thickness of the anterior wall of the right ventricle with the age of the subject (r = 0.375; p = 0.020) and moderate strength relationship between the thickness of the posterior wall of the left ventricle and BMI (r = 0.352; p = 0.030).Conclusions. The results of the study supplement the information available in the scientific literature on the thickness of the ventricles of the heart and the interventricular septum in healthy men with overweight in three age groups. The data obtained will be useful to doctors of functional diagnostics when performing echocardiography in matters of differentiation between norm and pathology.

Strength Characteristics of Concrete with Waste Polypropylene as Modifier for Pavement Construction

The demand for a better performing pavement and the need to convert the ever-growing polymer waste into beneficial use necessitated the need to develop and characterize a polypropylene modified concrete for use in pavement construction. This research focuses on characterizing the strength of concrete produced with waste polypropylene waste as modifiers for pavement construction. The materials used in this research are fine and coarse aggregates, cement and polypropylene waste chairs (PWC). Tests were performed on the aggregate and fresh concrete to determine their suitability and characteristics for use in concrete for pavement. Two concrete grades 1:2:4 and 1:3:6 was produced into 200 mm, 400 mm and 500 mm long paving stones on which compressive and flexural tests were performed. Results obtained showed that 400 mm 1:2:4 grade concrete has the highest compressive strength of 27.36 N/mm2 at 10% polypropylene composition. The 200 mm 1:2:4 concrete grade paving stone with 10% polyprpopylene composition has the highest flexural strength of 12.90 N/mm2. The 200 mm at 10% polypropylene composition correlation coefficient has that the highest value of 0.98 which better explains the compression-flexural strength relationship and validates the 200 mm length at 10% polypropylene composition paving stone as the most adequate length of paving stone for pavement construction. It was concluded that the 200 mm long 1:2:4 concrete grade paving stone at 10% polypropylene composition is the best length of paving stone that can give an adequate flexural strength which is the most important requirent in concrete pavement requirement.

Diagnosis of human-induced degradation of soils of the Azov-Cuban lowland

The work presents the observational data of soil cover structure dynamics, changes in soil composition and properties under the influence of anthropogenic impact. A decrease of 6.0-7.4% in the share of black soils (Chernozem) over 50 years of observations and a corresponding increase in the area of waterlogged soils associated with closed depressions have been revealed. Due to the high dynamism of soil density with changes in its moisture content, a criterion has been sought to characterize this dependence and a method has been proposed to describe it using dynamic curves. The amplitude of density fluctuations and its dependence on the severity of anthropogenic degradation – 59 -78% – has been established. Correlation analysis confirmed a medium strength relationship (determination coefficient 0.39-0.42) between shrinkage and specific surface area of initial degradation soils and a strong relationship (determination coefficient 0.79-0.86) in meadow-chernozem compacted soils. A strong correlation has been found between the volumetric shrinkage and fines content in the size distribution (determination coefficient 0.84-0.96). A new diagnostic criterion (“T” criterion) for the intensity of hydrometamorphism and, in general, for the physical aspect of anthropogenic soil degradation has been proposed.