scholarly journals APPLICATION OF ROLLER-COMPACTED CONCRETE IN FREIGHT TERMINALS

2020 ◽  
Vol 12 (0) ◽  
pp. 1-5
Author(s):  
Rafal Mickevič ◽  
Audrius Vaitkus
Keyword(s):  
Negative Impact ◽  
Experimental Studies ◽  
Concrete Pavements ◽  
Construction Costs ◽  
Roller Compacted Concrete ◽  
Fine Aggregates ◽  
Concrete Mix ◽  
Modulus Of Deformation ◽  
Pavement Structures ◽  
Materials Used

In these days constantly being looking for solution to reduce construction costs, the amount of materials used and the negative impact on the environment. Designing pavement structures with top layer of traditional concrete, the structures become very massive because of variation of concrete thickness from 20 cm to 29 cm according to the standard structures with concrete which are given in KPT SDK 19. An alternative to traditional concrete is roller-compacted concrete, the concrete with significantly larger fine aggregates which lead concrete mix to be non-slip. The roller-compacted mix can also achieve high concrete density and consolidation by rolling. The experimental studies were performed according to the guidelines of the “Guide for rollercompacted concrete pavements” and the automated StreetPave program. Twelve different variants of the pavement structure were used in the calculations, in which the main variables were: the modulus of deformation (Ev2), the thickness of stabilized layer (CTS) and the modulus of elasticity (E). Calculations were also performed for two scenarios, assuming that the amount of cracks appearing on the surface of the top layer after the design period would be 5% and 10%.

scholarly journals Roller Compacted Concrete – Best Practice Of Lithuania

2021 ◽  
Vol 1202 (1) ◽  
pp. 012010
Author(s):  
Audrius Vaitkus ◽  
Rafal Mickevič ◽  
Ovidijus Šernas
Keyword(s):  
Best Practice ◽  
Negative Impact ◽  
Industrial Area ◽  
Moisture Loss ◽  
Construction Costs ◽  
Heavy Load ◽  
Roller Compacted Concrete ◽  
Fine Aggregates ◽  
Pavement Structures ◽  
Materials Used

Abstract In these days constantly being looking for solution to reduce construction costs, the amount of materials used and the negative impact on the environment. Designing pavement structures with top layer of traditional concrete, the structures become very massive. An alternative to traditional concrete is roller-compacted concrete, the concrete with significantly larger fine aggregates which lead concrete mix to be non-slip. The roller-compacted mix can also achieve high concrete density and consolidation by rolling. Roller-compacted concrete is also an economical and fast-construction alternative for many pavement applications. In Lithuania, roller-compacted concrete as the top layer is an innovation and first application of it was few years ago. However, in recent years application of roller-compacted concrete increased in industrial areas and low-volume rural roads. The best practice of application of roller-compacted concrete was in Klaipeda Free Economic Zone, where roller-compacted concrete was used as the top layer of industrial area for heavy load traffic. Fresh roller-compacted concrete workability decreases with time, to reduce transportation time and avoid excessive moisture loss, which can cause problems in placement of roller-compacted concrete, mobile concrete batching plant used. Mobile concrete batching plant was located near construction site.

scholarly journals Functional Method of Designing Self-Compacting Concrete

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 267
Author(s):  
Tomasz Rudnicki
Keyword(s):  
Coarse Aggregate ◽  
Cement Mortar ◽  
Experimental Studies ◽  
Functional Method ◽  
Structural Viscosity ◽  
Self Compacting Concrete ◽  
Theoretical Assumptions ◽  
Concrete Mix ◽  
Selection Of ◽  
Double Coating

The article presents a new functional method of designing self-compacting concrete (SCC). The assumptions of the functional method of designing self-compacting concrete were based on the double coating assumption (i.e., it was assumed that the grains of coarse aggregate were coated with a layer of cement mortar, whereas the grains of sand with cement paste). The proposed method is composed of four stages, each of which is responsible for the selection of a different component of the concrete mix. The proposed designing procedure takes into consideration such a selection of the mineral skeleton in terms of the volumetric saturation of the mineral skeleton, which prevents the blocking of aggregate grains, and the designed liquid phase demonstrated high structural viscosity and low yield stress. The performed experimental studies, the simulation of the elaborated mathematical model fully allowed for the verification of the theoretical assumptions that are the basis for the development of the method of designing self-compacting concrete.

scholarly journals Properties of Materials Used in Roller Compacted Concrete Mixtures

2020 ◽  
pp. 61-72
Author(s):  
Ali Mardani ◽  
Sultan Husein Bayqra ◽  
Süleyman Özen ◽  
Zia Ahmad Faqiri ◽  
Kambiz Ramyar
Keyword(s):  
Roller Compacted Concrete ◽  
Concrete Mixtures ◽  
Properties Of Materials ◽  
Materials Used

scholarly journals CONSTRUCTION BUDGET AND ITS IMPACT ON CONSTRUCTION COSTS IN TIMES OF SANITARY CRISIS IN CORPORACION SANTA MARIA

2021 ◽  
Vol 9 (07) ◽  
pp. 112-118
Author(s):  
Dra. Flor Calvanapon Alva ◽  
◽  
Mg. Karina Cardenas Rodriguez ◽  
Silvia Cespedes Esquivel ◽  
Roxana Lujan Rodriguez ◽  
...  
Keyword(s):  
San Francisco ◽  
Negative Impact ◽  
Profit Margin ◽  
School Buildings ◽  
Construction Costs ◽  
Health Crisis ◽  
Documentary Analysis ◽  
Record Card ◽  
The Impact ◽  
Santa Maria

In order to determine the impact of the construction budget on the construction costs of the Santa Maria Corporation SAC-2020, an applied research was carried out, qualitative approach, non-experimental design and correlational scope, the sample are works executed in times of health crisis the school buildings No. 81540 San Francisco de Asis and No. 80638 Americo Aguilar Celis, in the province of Viru. Thestudytechniqueused was documentary analysis and the instrument was a record card. The data obtained were processed to evaluate the incidence of the variables by means of statistical tables where it was found that 4.29% additional materials were used for the first work and 4.33% additional for the second, with respect to the budget in the case of direct general expenses, 18.75% and 23.33% respectively, additional to the estimate. It is concluded that the construction budget has a negative impact on the construction costs of Corporacion Santa Maria SAC-2020 in times of sanitary crisis, observing relevant variations between the estimated and executed costs, not obtaining the expected profit margin noting that in the case of the first project the profit margin is only 10% of the estimate and in the second projectitis 0%.

scholarly journals Decision to paving solutions in road infrastructures based on life-cycle assessment

2016 ◽  
Vol 11 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Maria de Lurdes Antunes ◽  
Vânia Marecos ◽  
José Neves ◽  
João Morgado
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Decision Process ◽  
Life Cycle Cost ◽  
Road Network ◽  
Construction Costs ◽  
Road Pavement ◽  
Pavement Structures ◽  
Using Data ◽  
Term Performance

The construction and maintenance of a road network involve the expenditure of large budgets. In order to optimize the investments in road infrastructures, designers and decision makers should have the instruments to make the most suitable decision of paving solutions for each particular situation. The life-cycle assessment is an important tool of different road pavement solutions with this purpose. This paper presents a study concerning the life-cycle cost analysis of different flexible and semi-rigid paving alternatives, with the objective to contribute for a better support in the decision process when designing new pavement structures. The analysis was carried out using data on construction costs of certain typical pavement structures and taking into consideration appropriate performance models for each type of structure being selected. The models were calibrated using results from long term performance studies across Europe and the maintenance strategies considered have taken into account the current practice also found in the European context. Besides the life-cycle administration costs, the proposed methodology also deals with user and environmental costs through its inclusion in the decision process using multi-criteria analysis. It was demonstrated that this methodology could be a simple and useful tool in order to achieve the most adequate paving solutions of a road network, in terms of construction and maintenance activities, based simultaneously on technical, economic and environmental criteria.

scholarly journals STUDY OF THE EFFECTIVENESS OF VIBRATION ISOLATION OF UNCONVENTIONAL TOROIDAL ROPE VIBRATION ISOLATORS IN DIESEL UNITS VIBRATION ISOLATION SYSTEM

Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 110-114
Author(s):  
Minas Minasyan ◽  
Armen Minasyan ◽  
Aung Thant
Keyword(s):  
Power Plants ◽  
Vibration Isolation ◽  
Steel Wire ◽  
Experimental Studies ◽  
Wire Rope ◽  
Diesel Generator ◽  
Isolation System ◽  
Vibration Isolators ◽  
Before And After ◽  
Materials Used

The paper notes that the structure of the wire rope is one of the most suitable materials used as a fire-resistant elastic element of vibration-insulating structures and fasteners (vibration isolators). To solve the problems of vibration isolation of marine diesel power plants in the framework of development and improvement of the shock absorption system, the original patented elastic supports with elastic elements made of steel wire rope in the form of a torus are presented. When commercially available vibration isolators do not meet the relevant requirements of vibration protection of a particular object, the solution to the existing problem can be achieved by using the proposed wire rope vibration isolators. The technical results of the original patented inventions are: - equal stiffness in the horizontal plane - ensuring the reliability and high vibration efficiency of protection against impacts and shocks. The proposed designs of vibration isolators are easy (technological in manufacturing) to manufacture and assemble, reliable and durable - the service life is 10 years or more. Vibration efficiency is confirmed by the vibration acceleration spectra before and after the vibration isolator of the damping system of the ship diesel-generator DGA-500 and the diesel unit with a 2H 8.5/11 engine and water brake on a common sub-frame. The three-year trial life of the DGA-500 and experimental studies on a diesel unit with a 2H 8.5/11 engine and water brake on a common sub-frame confirms their efficiency and effectiveness.

Recovery of Hesperodiaptomus arcticus populations from diapausing eggs following elimination by stocked salmonids

1996 ◽  
Vol 74 (7) ◽  
pp. 1292-1297 ◽  
Author(s):  
Brian R. Parker ◽  
Frank M. Wilhelm ◽  
David W. Schindler
Keyword(s):  
Lake Sediments ◽  
Calanoid Copepod ◽  
Negative Impact ◽  
Experimental Studies ◽  
Fish Population ◽  
Alpine Lakes ◽  
Fish Stocking ◽  
Egg Bank ◽  
Diapausing Eggs ◽  
Gammarus Lacustris

Hesperodiaptomus arcticus, a predatory calanoid copepod, was eliminated from two alpine lakes within 6 years of stocking with salmonids. Using historical and contemporary Zooplankton and fish data, sediment analysis for diapausing eggs, and experiments on predation of Gammarus lacustris on diapausing eggs of H. arcticus, we assess the fate of these populations 35 years after fish stocking. In Pipit Lake, in which the trout introduction failed within 21 years, we propose that H. arcticus recovered as a result of hatching of diapausing eggs held in the sediments. In Snowflake Lake the diapausing egg bank was exhausted prior to the loss of the fish population 25 years after first stocking and H. arcticus recovery did not occur. Experimental studies indicate that G. lacustris predation on diapausing eggs probably occurs within the sediments. Combined with a 10-fold difference in G. lacustris density between Snowflake and Pipit lakes the results of the predation experiments imply that G. lacustris had a strong negative impact on the abundance of diapausing eggs held in Snowflake Lake sediments and therefore reduced the ability of the population to recover following perturbation.

MATHEMATICAL MODEL OF MATERIALS OF STRUCTURES AND ELEMENTS OF RESTORED SOIL DAMS FOR NUMERICAL CALCULATIONS

2021 ◽  
pp. 46-51
Author(s):  
V. YA. ZHARNITSKIY ◽  
◽  
A. P. SMIRNOV
Keyword(s):  
Negative Impact ◽  
Emergency Situation ◽  
Numerical Calculations ◽  
Stress And Strain ◽  
Operational Parameters ◽  
Reliable Operation ◽  
Operational Factors ◽  
Materials Used ◽  
Technical Operation ◽  
Strain Tensors

Identified in the process of analyzing the operation of the structure, in the conditions of its operation, allow to assess the actual reserves of the bearing capacity of the structure and take effective measures to restore the operational parameters. The main criteria influencing the choice of mathematical models of materials for structures and elements of soil dams are more consistent with the model of the equation of state connecting the components of stress and strain tensors, as well as the rate of their change, which are obtained and tested for numerical calculations and have a full set of constants for materials used in the calculations of earth dams, the choice of their structures (concrete,reinforced concrete, soils, etc.). Reliable operation of soil dams is possible only if all proper conditions are met. The causes of dam accidents and their damage must be known not only to eliminate errors at the design and construction stages, but also during their operation. In order to exclude the negative impact of operational factors on the safety of soil HTS, it is necessary not only to strictly observe the rules of technical operation and take measures to exclude the possibility of an emergency situation during technological operations at facilities, but also to have methods for predictive justification of the restoration of strength and operational indicators of structures and elements of soil dams.

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