Assessment of vibrocompaction quality of concrete mixtures for making reinforced-concrete products

2021 ◽  
pp. 53-56
Author(s):  
B. V. Gusev ◽  
◽  
L. M. Dobshits ◽  
A. A. Nikolaeva ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Poor Quality ◽  
Concrete Mixture ◽  
Uneven Distribution ◽  
Concrete Mixtures

The paper is devoted to determination of influence of vibration influence parameters at compaction of hard concrete mixtures designed for making reinforced-concrete sleepers. At poor quality compaction of a concrete mixture there is an uneven distribution of physical and mechanical indicators by length and width of products that negatively affects their future operation. The paper presents studies on determination of vibration influence parameters at compaction of concrete mixtures and provides recommendations on improvement of operation of existing technological lines.

DURABILITY PERFORMANCE AND DIMENSIONAL STABILITY OF POLYPROPYLENE FIBER REINFORCED CONCRETE

2018 ◽  
Vol 13 (2) ◽  
pp. 20-41 ◽  
Author(s):  
Ali Mardani-Aghabaglou ◽  
Süleyman Özen ◽  
Muhammet Gökhan Altun
Keyword(s):  
Reinforced Concrete ◽  
Dimensional Stability ◽  
Polypropylene Fiber ◽  
Pulse Velocity ◽  
Fiber Reinforced Concrete ◽  
Concrete Mixture ◽  
Fiber Reinforced ◽  
Concrete Mixtures ◽  
Durability Performance ◽  
Polypropylene Fiber Reinforced Concrete

In this study, the durability performance and dimensional stability of polypropylene fiber reinforced concrete mixture were investigated. For this purpose, two series of concrete mixtures, including a 0.45 water/cement ratio was prepared both in the absence and presence of fiber. A CEMI 42.5 R type portland cement and crushed limestone aggregate with a maximum particle size of 25 mm were used. In addition to the control mixture without fiber, three different concrete mixtures were prepared by adding polypropylene fiber as 0.4%, 0.8% and 1% of total volume into the mixture. The time-dependent fresh state properties, strength, ultrasonic pulse velocity, transport properties, drying shrinkage and freeze-thaw resistance of concrete mixtures, sodium sulfate attack and abrasion were investigated comparatively. Test results demonstrated that utilization of fiber affected the fresh properties of the concrete mixtures negatively. However, the 0.8% fiber-bearing mixture showed the highest performance in terms of durability and dimensional stability. Beyond this utilization ratio, the durability performance of the concrete mixture was negatively affected. The risk of nonhomogeneous dispersion of the fiber in the mixture was relatively high in the excess fiber-bearing mixture. Consequently, with the formation of flocculation in the mixture the void ratio of concrete mixture increased.

scholarly journals Experimental Testing of Reinforced Concrete Deep Beams Designed by Strut-And-Tie Method

2020 ◽  
Vol 10 (18) ◽  
pp. 6217
Author(s):  
Anka Starčev-Ćurčin ◽  
Andrija Rašeta ◽  
Mirjana Malešev ◽  
Danijel Kukaras ◽  
Vlastimir Radonjanin ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Experimental Testing ◽  
Deep Beams ◽  
Simply Supported ◽  
Strut And Tie ◽  
The Third ◽  
Variation Parameter ◽  
The One

The aim of the research presented in this paper is the experimental confirmation of the numerically defined shapes of the Strut-and-Tie models, designed according to the EN 1992-1-1 recommendations, and obtained from the software “ST method”. Three reinforced concrete deep beams with openings were tested. Each of them had the same dimensions and quality of the material characteristics. The specimens, constructed as simply supported beams, were loaded with two concentrated forces and were tested for bending until failure. Each specimen was reinforced with different reinforcement layout determined by variation parameter β, incorporated in the software “ST method”. For the determination of the Strut-and-Tie models, all of the reinforcement layouts were equally favored in the first specimen (β = 1.0 for 0°, 45°, and 90°), only the horizontal direction was favored in the second (β = 1.0 for 0°), while in the third specimen the one at the angle of 45° (β = 1.0 for 45°). Based on the results of experimental research, it was concluded that the behavior of loaded members was in agreement with the proposed shapes of the Strut-and-Tie models that were used for their design, and it was confirmed that the program “ST method” can be used for obtaining Strut–and-Tie models.

scholarly journals Determination of prioritization for maintenance of the upper structure of truss bridge

2019 ◽  
Vol 276 ◽  
pp. 01036 ◽  
Author(s):  
Heni Fitriani ◽  
M. Ade Surya Pratama ◽  
Yakni Idris ◽  
Gunawan Tanzil
Keyword(s):  
Poor Quality ◽  
Truss Bridges ◽  
Vehicle Load ◽  
Bridge Maintenance ◽  
Wide Range ◽  
Maintenance Systems ◽  
Truss Bridge ◽  
Hierarchy Process

Bridge maintenance is one of the major issues of infrastructure problems. Deterioration of a bridge’s structure will continuously increase without proper maintenance. This condition will adversely affect the service life of a bridge. Moreover, the damage will also have a direct impact on structural and functional failure of the bridge. This paper aims at identifying the damages of truss bridges and determining the most significant criteria and sub-criteria used in prioritizing bridge maintenance. Analytical Hierarchy Process (AHP) was used to assess the most important criteria that give significant weight to bridge maintenance analysis. The objects of research were nine truss bridges with a wide range of types and levels of damage. It was found that there were approximately 900 m' of components damaged at the railing of Baruga Bridge and 227 m' truss damages due to poor quality of the galvanized paint. Furthermore, based on the analysis, the most significant criteria were the level of damage (27.6%), the technical aspects (25.7%), the finance (21%), the vehicle load (13.6%) and the resources (12%). The results of this research showed important findings in determining the priority scales for bridge repair and maintenance systems.

Determination of the Influence of Carbonation of Concrete and Corrosion of Steel on Reinforced Concrete Condition

2015 ◽  
Vol 1124 ◽  
pp. 225-230 ◽  
Author(s):  
Kristýna Timcakova ◽  
Daniela Štefková ◽  
Zdeněk Chobola
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Poor Quality ◽  
Protective Properties ◽  
Impact Echo ◽  
Concrete Condition ◽  
Almost All ◽  
Corrosion Of Steel ◽  
Impact Echo Method

Almost all reinforced concrete structures which are exposed to weather effects are threatened by corrosion. The corrosion of steel elements in structures has an influence on lifetime these constructions and adversely affects their properties. However, the steel in concrete structures is protected against corrosion due to the properties of concrete such as high pH or impermeability, but if the concrete is of poor quality and his protective properties are insufficient the corrosion can occur. A problem causes the action of carbon dioxide which has the effect of lowering the pH below the critical value and thereby accelerating the corrosion.Non-destructive methods such as Impact-echo method offer the possibility of easy and quickly detection of initial damage of structure and thus can prevent the occurrence of permanent damage to the whole construction.This article describes the development of corrosion which is caused by carbonation of the concrete and supported by action of chlorides by using Impact-echo method. The paper presents results obtained on the reinforced concrete samples with one steel rod passing through the center. After carbonation concrete the samples were exposed accelerated controlled degradation in aqueous NaCl solution for 4 months.

DETERMINATION OF OPTIMUM QUANTITY OF BITUMEN IN ASPHALT CONCRETE MIXTURES

2002 ◽  
Vol 8 (1) ◽  
pp. 73-76
Author(s):  
Kęstutis Vislavičius
Keyword(s):  
Personal Computer ◽  
Asphalt Concrete ◽  
Concrete Mixture ◽  
Computer Programme ◽  
Narrow Fraction ◽  
Minimum Quantity ◽  
Concrete Mixtures ◽  
Optimum Quantity

The problem of calculating the quantity of a required bitumen is formulated as follows: from certain mineral materials the grading curves and narrow fraction bitumen receptivities which are known to determine the composition of an asphalt concrete mixture that satisfies grading limitations of mineral materials and contains minimum quantity of a required bitumen. Mathematical analogues of the problem are presented. A personal computer programme for calculating the minimum quantity of a required bitumen is prepared, and some example problems are solved. An analysis of the results is presented.

scholarly journals Production and production over-supply in construction: estimating unsold stock in Italy

2014 ◽  
Vol 7 (4) ◽  
pp. 506-523 ◽  
Author(s):  
Andrea Ciaramella ◽  
Alberto Celani
Keyword(s):  
Real Estate ◽  
Poor Quality ◽  
Real Estate Market ◽  
Content Type ◽  
The Real Estate ◽  
Real Estate Sector ◽  
Critical Issues ◽  
Definition Of

Purpose – The aim of the article is to identify the limitations and critical issues in the way information in the real estate sector in Italy is currently managed, and propose the principles of a method that would provide information and comparison of the phenomenon of over-supply and non-rational land use. This study is based on a series of assumptions, the first of which is a definition of “unsold”, deemed to mean “the amount of new housing units neither occupied nor sold nor rented”. In effect, unsold stock can be considered as over-supply of construction. Design/methodology/approach – The article identifies the critical aspects in the determination of unsold real estate in Italy, starting from the available data and research already carried out; the results are often contradictory. The comparison with programming systems of building production adopted in other countries allows identification of the guidelines that can be used to better understand and combat the phenomenon. Findings – The assessment of the state -of-the-art provides a clear picture of the shortcomings and potential of the tools used to date to meet the need of studying a complex phenomenon with many obscure points. Following the empirical analysis comes out a picture of inefficiencies due to the poor quality of information, as well as the reluctance of data-sharing and -integration procedures by the institutional and market players. Research limitations/implications – The research produces solutions addressed to the Italian situation, but it identifies systems and methods used in other countries. Practical implications – The article suggests the collection systems and management information that can be used for a more accurate knowledge of unsold real estate. Social implications – The article focuses on some of the limits of the Italian real estate market, highlighting the need for greater transparency and how this can contribute to a more conscious approach to the market. Originality/value – The article seeks to provide the necessary answers to those who must understand the reasons of harmful effects for the market, such as overproduction; besides some models focused on three areas – the procedures, the organization and the market – are also proposed.

scholarly journals Effect of Zeolite on the Compressive Strength of Concrete with Different Types of Cement

2022 ◽  
Vol 955 (1) ◽  
pp. 012002
Author(s):  
I Sudarsono ◽  
S I Wahyudi ◽  
H P Adi ◽  
M D Ikval
Keyword(s):  
Compressive Strength ◽  
Concrete Mixture ◽  
Test Results ◽  
Concrete Mixtures ◽  
Material Component ◽  
Optimum Proportion ◽  
Different Types ◽  
Increasing Demand ◽  
Type V

Abstract Concrete is a material component in coastal area construction. With the increasing demand for concrete for construction purposes, there have been various innovations in concrete mixtures to improve the quality of the concrete, including the compressive strength value of concrete. In the concrete mixture, the researchers also add additive to the concrete mixture, one alternative is natural zeolite which is widely found in the earth. Research by testing concrete samples with variations of the zeolite mixture 0%, 15%, and 25% uses cement type V. The test results are then compared with the results of other studies using different types of cement. Comparative studies of zeolite concrete test with different types of cement show that the optimum proportion of zeolite is around 10% to 20% of the weight of cement to get the best compressive strength value.

scholarly journals Моніторинг безпечності та якості продуктів забою свиней, отриманих в умовах Одеської області

2017 ◽  
Vol 19 (77) ◽  
pp. 148-152
Author(s):  
M.S. Khimich ◽  
A.M. Gorobei ◽  
F.V. Kozulin ◽  
V.V. Zhekov
Keyword(s):  
Poor Quality ◽  
Modern Technology ◽  
Post Mortem ◽  
Food Markets ◽  
Preventive Approach ◽  
Invasive Diseases ◽  
Livestock Products ◽  
Pig Carcasses

In accordance with the modern requirements of the international control system (HACCP), it is necessary to abandon the control of the final product for the purpose of identifying shortcomings, but to proceed to the preventive approach of eliminating potential sources of danger at all stages of production. A step-by-step system for controlling the quality of livestock products, in particular meat, in the absence of modern technology of primary processing and quality veterinary and sanitary control, is complex. Therefore, to ensure the safety and quality of meat, it is necessary to improve and scientifically justify the methods of their control, bringing it closer to international requirements. The purpose of our research was to monitor the safety and quality of slaughter products for pigs obtained in the conditions of the Odessa region. The material of the research was reporting on veterinary medicine (Form No. 6-vet., Form No. 5- vet., Form No. 2a-vet.) In the districts of the Odessa region for 2014–2016, which was processed statistically. The analysis has established that for 2014–2016. In the investigated areas, only 28846 pigs were slaughtered, and 74.48% of the slaughter took place. It was found that according to the results of the pre-blast inspection and post-mortem veterinary examination of pig carcasses, 83 cases of diseases, echinococcosis, were detected during the reporting period. For the reporting years, 17103 carcasses of pigs were supplied to the agro-food markets of the study areas. Employees of laboratories for veterinary and sanitary examination in the markets conducted 65417 laboratory studies: all carcasses of pigs were examined organoleptically (including cooking breakdown), trichinoscopy and studies for phychosis and other parasitic diseases were performed; The determination of physicochemical parameters and bacterioscopy of mascara were carried out in individual cases; radiological and other studies were not conducted. During the veterinary and sanitary examination, 662 cases of diseases were detected in the laboratories of veterinary and sanitary examination in the markets: 65 cases of non-communicable diseases and 597 cases of invasive diseases. And draws attention to the fact that 99.83% of the identified invasive diseases was echinococcosis. Comparative analysis of the results on the detection of cases of echinococcosis, depending on the location of Veterinary control, found significant discrepancies– after post-mortem veterinary and sanitary control, only 7.26–26.27% of cases are detected, in comparison with the results of veterinary and sanitary examination of slaughter products in laboratories for veterinary and sanitary examination In the markets. This imbalance, in our opinion, can be related to homestead slaughter and poor quality post-mortem Veterinary control during it. Summarizing the obtained results of the analysis, we can conclude that the management system for the safety and quality of slaughter products in pigs in the regions of the Odessa region at the present stage still relies on the analysis of the final product, not taking into account the preventive approach.

scholarly journals Design and implementation of fish freshness detection algorithm using deep learning

2021 ◽  
Vol 944 (1) ◽  
pp. 012007
Author(s):  
D F Anas ◽  
I Jaya ◽  
Nurjanah
Keyword(s):  
Detection Algorithm ◽  
Poor Quality ◽  
Fresh Fish ◽  
Traditional Markets ◽  
Organoleptic Test ◽  
Fish Samples ◽  
Medium Quality ◽  
Euthynnus Affinis

Abstract Organoleptic assessment of fresh fish includes specifications for the quality of the eyes, gills, mucus, odor, texture and flesh (color and appearance). However, not everyone has knowledge about it. This research uses the tiny yolov2 to facilitate the determination of fish freshness levels (good quality, medium quality, poor quality) correctly and fast. There are a few stages in this research, included organoleptic test accompanied by taking fish eye image dataset every hour, processing organoleptic test data labeling, training, and validation. There are three types of fish used, consists of Rastrelliger, Euthynnus affinis, and Chanos chanos. Detection of fish freshness level for three species was successfully carried out with the result of average precision is 72.9%, average recall is 57.5%, and accuracy is 57.5%. The factors that affect the prediction results in this study is the collection of datasets before the training process is carried out consisting of fish samples obtained from traditional markets, which are considered inadequate so that it affects the organoleptic test process itself, the organoleptic test that was carried out as a reference for image sorting was considered inaccurate because it used less than 30 untrained panelists and dataset imbalance.

scholarly journals Quantitative Colorimetric Analysis of Aloe Polysaccharides as a Measure of Aloe Vera Quality in Commercial Products

2005 ◽  
Vol 88 (3) ◽  
pp. 684-691 ◽  
Author(s):  
Alexis R Eberendu ◽  
Gabriela Luta ◽  
Joshua A Edwards ◽  
Bill H Mcanalley ◽  
Brice Davis ◽  
...  
Keyword(s):  
Colorimetric Assay ◽  
Aloe Vera ◽  
Accurate Method ◽  
Quantitative Information ◽  
Poor Quality ◽  
Colorimetric Analysis ◽  
Beneficial Effects ◽  
Aloe Gel

Abstract Aloe Vera inner leaf gel has been used as a medicinal remedy for many years. Yet some aloe products do not demonstrate beneficial effects, indicating that poor quality products are reaching the market. Therefore, an efficient and accurate method is needed to evaluate the quality of aloe products. This paper describes a quick, quantitative colorimetric assay that has been developed for the determination of glucomannan in aloe gel and products. With this method, interference by non-aloe polysaccharides or other extraneous components was absent or negligible. Data indicate that the glucomannan can be determined at parts per million (mg/L) in aqueous solutions with an accuracy of 100 ± 5% at a 10 mg/L concentration. The correlation coefficient is 0.999, and linearity is from 0.9 to 72.7 mg/L in the test solution. The method is inexpensive, simple, sensitive, and reproducible. This method was applied to determine the polysaccharide content of commercial aloe products. Both qualitative and quantitative information can be obtained in about 5 min.

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