In this article, authors consider the nomenclature of the parameters of the annual production program, obviously affecting the intensity of work on the objects and, consequently, on the timing of the fulfillment of ob...
In this article, authors consider the nomenclature of the parameters of the annual production program, obviously affecting the intensity of work on the objects and, consequently, on the timing of the fulfillment of obligations under general construction contracts in general. A systematic analysis of these factors is carried out with a study of the degree of influence on the duration of the construction project. As a result of these studies, the authors present a model of the annual production program of a construction organization in terms of the input significant parameters.
This paper presents an experimental investigation of strengthened reinforced concrete structure by bonded natural fiber composite materials. Nonetheless, the composite plates are externally constituted of a matrix bas...
This paper presents an experimental investigation of strengthened reinforced concrete structure by bonded natural fiber composite materials. Nonetheless, the composite plates are externally constituted of a matrix based on epoxy adhesive in which the aligned continuous natural fibers are embedded. In recent years, the natural fibers are of great interest as a result of policies to reduce the negative impact on the environment. They are a renewable source, helping to capture carbon dioxide during their cultivation. Numerous technical, economic, and environmental advantages such as low cost, high strength-to-weight ratio, low density, and non-corrosive properties make them very attractive to use. The objective of this research is to assess the strengthened capacity of natural fibers. This research mainly used hemp and flax natural fibers. So, these natural fibers are an alternative to synthetic reinforcing fibers like carbon fiber or glass fiber, which are widely used in civilengineering. This article briefly presents the results of the tests carried out on concrete prismatic specimens strengthened by external bonding different composite plates based on natural fibers. The tests were presented by examining the influence of reinforcement on the ultimate capacity and the element of rigidity. The results show a significant increase in the ultimate load of the strengthened concrete prismatic specimens compared to the reference specimen. The cracking and failure modes are presented. The results show that the natural fibers are a good alternative to glass and carbon fibers.
The potential of cost reduction by efficient digital communication in building processes in Sweden has been investigated to be 15-25% of the building sum. An important part of this potential is by using building infor...
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Conventional PCC pile technique has been widely used as embankment piles for highway construction in China. To further improve the PCC pile capacity, the expansive concrete technique has been applied to the PCC pile t...
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Conventional PCC pile technique has been widely used as embankment piles for highway construction in China. To further improve the PCC pile capacity, the expansive concrete technique has been applied to the PCC pile to replace the normal concrete recently. The use of expansive concrete for the PCC pile could increase the pile diameter as well as the contact pressure at the pile-soil interface due to the expansion process of concrete, which allows the improved PCC pile to provide higher capacity than the conventional PCC pile. This paper presents a theoretical model for the new improved PCC pile using expansive concrete technique. The model is formulated by assuming the PCC pile installation process as large strain undrained cylindrical cavity expansion and the subsequent pile shaft expansion combined with soil consolidation process is simulated by the small strain cylindrical cavity expansion combined with strain-controlled consolidation. Then, similarity solution technique is used to solve the problem of cavity expansion in modified cam Clay （MCC） model, while the strain-controlled consolidation is calculated through the finite difference method （FDM）. Subsequently, the suitability of the cavity expansion solution in the interpretation of the PCC pile installation is verified by comparing the calculated excess pore pressure with the measured value in an instrumented field test. The stress changes and excess pore pressure during the PCC pile installation and subsequent pile shaft expansion are investigated by means of parametric study. The proposed theoretical model first reveals and quantifies the fundamental mechanism of the PCC pile using expansive concrete technique and it provides a theoretical basis for developing design methods of the new improved PCC pile in the future.
The article deals with the research results of concrete destruction processes by different types of external impact. The materials were obtained by the Samara research school of architecture and construction academy. ...
The article deals with the research results of concrete destruction processes by different types of external impact. The materials were obtained by the Samara research school of architecture and construction academy. The paper analyzes the process of concrete destruction and determines its main flow stages, depending on the amount of released energy of crack formation. Initial parameters of concrete structure are proposed, including: surface energy, modulus of elasticity and Poisson's coefficient. The authors paid special attention to kinetic characteristics including tendency of concrete crack formation and crack formation intensity. The combination of kinetic characteristics is given as a criterion for concrete durability assessment. Quantitative dependence of kinetic characteristics on moisture and porosity is confirmed.
This article presents the results of the bottom ash from Circulating fluidized Bed Combustion (CFBC). Ashes were modified by grinding in their physical parameters. For this treatment was used the tumbling ball mill at...
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The primary advantage of geo polymeric concrete is the decrease in ecological effect in agreement with the concept of sustainable development. The present investigation thinks about the quality, and transport properti...
The primary advantage of geo polymeric concrete is the decrease in ecological effect in agreement with the concept of sustainable development. The present investigation thinks about the quality, and transport properties of GGBS–and fly debris based geopolymer mortars with different level of steatite powder. The main variables investigated were the hybrid binder of geopolymer mortar. In this present study fly ash and GGBS is partial replacement with different amounts of steatite powder (soap stone) 0%,10%, 20%, 30%, 40% & 50% to obtained the mechanical properties such as compressive strength and split tensile strength. For comparison, one mixture of ordinary portland cement mortar (OPC) is also studied. The alkali activators are prepared by combining NaOH and Na2SiO3 solution in the ratio of 2.5 and NaOH concentration 10M. The flyash based Geopolymer mortar specimens are heat curing (oven dry) at 70°C for 48 hours and ambient curing was done in GGBS based Geopolymer mortar. Test results were obtained that, when increasing percentages of fly ash partial replaced with the steatite powder is gradually increased the strength and the proportion of steatite powder 30% are the optimum range value.
Cadmium zinc telluride (CdZnTe) semiconductor has applications in the detection of X-rays and gamma-rays at room temperature without having to use a cooling system. Chemical etching and chemo-mechanical polishing are ...
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Cadmium zinc telluride (CdZnTe) semiconductor has applications in the detection of X-rays and gamma-rays at room temperature without having to use a cooling system. Chemical etching and chemo-mechanical polishing are processes used to smoothen CdZnTe wafer during detector device fabrication. These processes reduce surface damages left after polishing the wafers. In this paper, we compare the effects of etching and chemo-mechanical polishing on CdZnTe nuclear detectors, using a solution of hydrogen bromide in hydrogen peroxide and ethylene glycol mixture. X-ray photoelectron spectroscopy (XPS) was used to monitor TeO2 on the wafer surfaces. Current-voltage and detector-response measurements were made to study the electrical properties and energy resolution. XPS results showed that the chemical etching process resulted in the formation of more TeO2 on the detector surfaces compared to chemo-mechanical polishing. The electrical resistivity of the detector is of the order of 1010 Ω-cm. The chemo-mechanical polishing process increased the leakage current more that chemical etching. For freshly treated surfaces, the etching process is more detrimental to the energy resolution compared to chemo-mechanically polishing.
This paper presents a design and construction schemes of a pipe jacking project in Kunming, China in detail. The underpass, having a width of 6.9 m and a height of 4.9 m, was jacked 46m in water-filled clay under a bu...
This paper presents a design and construction schemes of a pipe jacking project in Kunming, China in detail. The underpass, having a width of 6.9 m and a height of 4.9 m, was jacked 46m in water-filled clay under a busy viaduct with 4.5 m overburden soil., Some adjustments have been made to the construction process due to the characteristics of the soil layer, the surrounding environment and the existing pipeline. During the whole construction process: the pipe jacking passes through the shallow confined aquifer with high water content and high void ratio, it is easy to produce rheology. In addition, the attitude control of whole tube is also a difficulty, and some adjustments have been made to this problem; the monitoring scheme has also been adjusted accordingly. In general, this project is completed successfully and the traffic on ground and viaduct runs well during the whole construction process.
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