scholarly journals The quality index for produced concrete and reliability in relation to the small size sample

2014 ◽  
Vol 13 (2) ◽  
pp. 135-141 ◽  
Author(s):  
Izabela Skrzypczak ◽  
Lidia Buda-Ożóg

Compliance criteria for the sample size n = 3 have a lot of disadvantages [5,6,7] and they can affect the reduction of quality of produced concrete and, consequently,  they can cause too much risk of the recipient (the investor) side. Therefore, the effect of the sample size on the defined quality index of produced concrete has been evaluated. The effect of the sample size and standard deviation on the reliability index of reinforced concrete structures has also been determined.The impact analysis of compliance criteria on the reliability index of reinforced concrete structures was conducted for a compression column. The obtained values of the reliability index results confirm the correctness of the quality index formula and concrete quality proposed in method of defining.

Author(s):  
A. Finkelshteyn ◽  
A.L. Bimman

Abstract Considering the number of concrete structures such as bridges, overpasses, trestles etc., their maintenance and repair form a significant part of the highway administration budget. Cathodic protection is becoming more popular because it helps reduce maintenance and renovation costs. Arc-sprayed zinc and zinc/aluminum alloy coatings are widely used in cathodic protection systems. The surface preparation of concrete is critical to the quality of coating and hence, the quality of the cathodic protection. Typically, sandblasting with surface brushing is used as preparation. This method has several technical, economic and ecological deficiencies: weather/humidity limitations, difficult removal of organic contaminants from the surface, an irrevocable loss of blasting media, high dust level, etc. An objective of this proceeding is to describe a plasma cleaning process as a successful alternative to sandblasting and to show the possibilities of combined plasma cleaning/coating process for the cathodic protection of reinforced concrete structures. This environmentally friendly process will result in better anodic coatings at lower cost and fewer concrete structure repairs.


2019 ◽  
Vol 968 ◽  
pp. 267-280
Author(s):  
Olha Ahaieva ◽  
Vasyl M. Karpiuk ◽  
Oleksandr Posternak

The paper studies the influence of various constructive factors on the parameters of design reliability and bearing capacity of span prestressed reinforced concrete structures. With the help of experimental design techniques and an effective software package, 12 adequate mathematical models have been developed and brought to the level of practical use. They allow to predict the reliability and bearing capacity of normal and oblique sections of specified structures for any combinations of concrete class, reinforcement class and reinforcement ratio. These models also allow to investigate both the direction of the change in bearing capacity and reliability index of prestressed reinforced concrete elements with the change of the above-mentioned factors, which is useful in solving some optimization problems at the design stage.


Author(s):  
B.M. Aubakirova ◽  
◽  
E.R. Onlasynov ◽  

This article examines the analysis of the main factors affecting the quality of the restoration work of concrete and reinforced concrete structures. The ways of increasing the capacity of repair concrete by increasing the adhesion strength are shown. As a result, its value should not be lower than the tensile strength of concrete.


1992 ◽  
Vol 138 (1) ◽  
pp. 111-116 ◽  
Author(s):  
Masatoshi Ueda ◽  
Tetsuo Shirai ◽  
Yasuo Doi ◽  
Masato Otaki ◽  
Hiroshi Saito

2013 ◽  
Vol 482 ◽  
pp. 118-122
Author(s):  
Jing Bo Sun ◽  
Yong Zhi Zuo ◽  
Hai Wen Teng ◽  
Tao Zhang ◽  
Huan Liu

The reason of most accidents in the construction engineering are due to the complicated nature of concrete composition, shortcomings during the construction process, equipment and many other reasons. Reinforced concrete quality account for a large percentage of engineering accidents. In this paper, reinforced concrete structures accident type and its causes were classified and summarized through the summarizing and sorting of different cases, and the relationship between them was analyzed and expounded.


Author(s):  
A. Liashkevich

In this article the problem of assessment of working documentation quality in terms of trustworthiness of the calculation of area of main reinforcement of reinforced-concrete structures is reviewed. In spite of development of automated designing systems, no application solutions for fully automated check of quality of working documentation for reinforced-concrete structures as regards sufficiency and necessity of reinforcement of them have been proposed until now. Moreover, this rather routine procedure can be fully automated to exclude the subjective nature of its results. Artificial neural networks (ANN) constitute the most promising mathematical model for this purpose. There are known examples demonstrating the possibility of applying the ANN for various types of calculations and analysis of experimental data for reinforced-concrete structures. In particular, the ANN allows predicting the actual deformation parameters of reinforced-concrete structures with significantly greater accuracy than any of the current national design standards. The article presents the results of calculations of reinforcement and sag for various input parameters using the example of reinforced-concrete slab structure. Using the simplest ANN with one hidden layer over the entire training sample, the predicted values with sufficient accuracy for practical use were obtained. It has been established that ANN makes it possible to predict effectively not only values of the required reinforcement for slab structures, but also their deformation. Within the framework of BIM-technologies used currently in building design, the use of ANN to assess the quality of ready-made design documentation in terms of reinforcement will reduce considerably the cost and time of relevant examinations with significantly higher trustworthiness of their results.В статье рассмотрена задача оценки качества рабочей документации в части достоверности расчета площади рабочей арматуры железобетонных конструкций. Несмотря на развитие систем автоматизированного проектирования, до настоящего времени не предложено прикладных решений для полностью автоматизированной проверки качества рабочей документации железобетонных конструкций на предмет достаточности и необходимости их армирования. При этом эта весьма относительно рутинная процедура может быть полностью автоматизирована для исключения субъективного характера ее результатов. Наиболее перспективной математической моделью для этой цели являются искусственные нейронные сети (ИНС). Известны примеры, демонстрирующие возможность прикладного применения ИНС для различного рода расчетов и анализа экспериментальных данных для железобетонных конструкций. В частности, ИНС позволяет с существенно большей точностью прогнозировать фактические параметры деформирования железобетонных конструкций, чем любые из действующих национальных норм проектирования. В статье на примере железобетонной плитной конструкции приведены результаты расчетов армирования и прогиба при различных значениях входных параметров. С помощью простейшей ИНС с одним скрытым слоем по всей обучающей выборке получены прогнозные значения с достаточной для практического их использования точностью. Установлено, что ИНС позволяет достаточно эффективно прогнозировать не только значения требуемого армирования для плитных конструкций, но и их деформации. В рамках используемых в настоящее время в строительном проектировании BIM-технологий применение ИНС для оценки качества готовой проектной документации в части армирования позволит значительно сократить стоимость и сроки соответствующих экспертиз при существенно более высокой достоверности их результатов.


2021 ◽  
Vol 2131 (5) ◽  
pp. 052066
Author(s):  
V Molodin ◽  
S Leonovich ◽  
S Shpanko

Abstract Concrete adhesion is a decisive factor in restoring performance of reinforced concrete structures. Peeling of the repair concrete is observed, during the structures restoring that have been in operation for a long time in aggressive conditions. The studies of the carbon dioxide effect on cement stone showed crystalline framework destruction of the material and a decrease in its cohesive strength. This has a significant effect on grip. The use of forced heating of the repair mixture when it is placed in contact with the restored structure leads to the temperature gradients that enhance thermal diffusion and thus the impregnation of the damaged cement stone with the liquid phase from the repair concrete mixture. Crystallizing, the cement dissolution products form a new crystalline structure in the damaged cement stone, which enhances its cohesive strength and binds the repair concrete to the intact concrete structure of the restored structure, ensuring adhesion quality.


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