scholarly journals Evaluating the efficiency of the fluidity retention of ready-mix concrete during the transportation of it to the construction site

2018 ◽  
Vol 230 ◽  
pp. 03005
Author(s):  
Oleksii Kabus ◽  
Larisa Butska ◽  
Olga Makarenko ◽  
Lidiya Pershina ◽  
Andriy Tymoshchenko
Keyword(s):  
High Water ◽  
Construction Site ◽  
Chemical Additives ◽  
Concrete Mixtures ◽  
Individual Solution ◽  
Concrete Mix ◽  
Gradual Introduction ◽  
The Cost ◽  
Ready Mix Concrete

The work is devoted to the study of changes in the time of mobility of concrete mixtures, which are used for commercial concrete with monolithic construction. The in-situ concrete quality depends on the uniformity, viability and workability of the concrete mix intended for the transportation, unloading and workability at the construction site. One of the techniques used for the solution of this problem can be step-by-step addition of chemical admixtures or introduction of setting retarders whose efficiency is expressed in an increased resiliency of the concrete mix that is extended by two and more hours. Each solution has its advantages and drawbacks; therefore the efficiency can only be estimated under specific conditions taking into account the cost of concrete mix and opportunities for the realization of each individual solution. Were received results showing the presence of a problem of mobility loss of concrete mixtures with chemical additives of high water-reducing action. The use of such technological techniques as increasing the initial mobility and gradual introduction of supplements to superplasticizer proved to be effective technological solutions.

scholarly journals Concrete sustainability with very high amount of fly ash and slag

2009 ◽  
Vol 2 (3) ◽  
pp. 244-253 ◽  
Author(s):  
G. C. Isaia ◽  
A. L. G. Gastaldini
Keyword(s):  
Fly Ash ◽  
Construction Material ◽  
Ternary Mixtures ◽  
Sustainable Construction ◽  
Concrete Mixtures ◽  
Binary And Ternary Mixtures ◽  
Concrete Mix ◽  
Mineral Additions ◽  
The Mean ◽  
The Cost

This article approaches concrete mix designs where cement is replaced by high amounts of slag and fly ash, with the purpose of turning it into a more sustainable construction material, that is, an authentic green concrete. Mix proportions with fly ash, ground-blasted furnace slag, and Portland cement were studied in binary and ternary mixtures for compressive strength levels of 40 MPa and 55 MPa. The replacement of cement with mineral additions ranged from 50% to 90% in mass. Mean decreases of 55% in the energy consumption, 78% in the CO² emissions, and 5% in the cost of the concrete m³, plus an increase of 40% in the mean index of durability were obtained, all ofwhich compared to the 40-MPa reference concrete. This study attests the technical, economical and environmental potentialities for theuse of concrete mixtures with until 90% of fly ash.

scholarly journals Seawater Absorption and Adhesion Properties of Hydrophobic and Superhydrophobic Thermoset Epoxy Nanocomposite Coatings

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 272
Author(s):  
Ayman M. Atta ◽  
Mohamed H. El-Newehy ◽  
Meera Moydeen Abdulhameed ◽  
Mohamed H. Wahby ◽  
Ahmed I. Hashem
Keyword(s):  
Thermal Stability ◽  
Oleic Acid ◽  
Salt Spray ◽  
Adhesion Properties ◽  
In Situ Modification ◽  
Long Time ◽  
Seawater Environment ◽  
Thermoset Epoxy ◽  
The Cost

The enhancement of both thermal and mechanical properties of epoxy materials using nanomaterials becomes a target in coating of the steel to protect it from aggressive environmental conditions for a long time, with reducing the cost. In this respect, the adhesion properties of the epoxy with the steel surfaces, and its proper superhyrophobicity to repel the seawater humidity, can be optimized via addition of green nanoparticles (NPs). In-situ modification of silver (Ag) and calcium carbonate (CaCO3) NPs with oleic acid (OA) was carried out during the formation of Ag−OA and CaCO3−OA, respectively. The epoxide oleic acid (EOA) was also used as capping for Ca−O3 NPs by in-situ method and epoxidation of Ag−OA NPs, too. The morphology, thermal stability, and the diameters of NPs, as well as their dispersion in organic solvent, were investigated. The effects of the prepared NPs on the exothermic curing of the epoxy resins in the presence of polyamines, flexibility or rigidity of epoxy coatings, wettability, and coatings durability in aggressive seawater environment were studied. The obtained results confirmed that the proper superhyrophobicity, coating adhesion, and thermal stability of the epoxy were improved after exposure to salt spray fog for 2000 h at 36 °C.

scholarly journals Black Soldier Fly Larval Valorization Benefitting from Ex-Situ Fungal Fermentation in Reducing Coconut Endosperm Waste

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 275
Author(s):  
Chung Yiin Wong ◽  
Kunlanan Kiatkittipong ◽  
Worapon Kiatkittipong ◽  
Seteno K. O. Ntwampe ◽  
Man Kee Lam ◽  
...  
Keyword(s):  
Principal Component ◽  
Correlation Study ◽  
Statistical Correlation ◽  
Waste Reduction ◽  
Ex Situ ◽  
Larval Feeding ◽  
Rhizopus Oligosporus ◽  
Black Soldier Fly ◽  
The Cost

Oftentimes, the employment of entomoremediation to reduce organic wastes encounters ubiquitous shortcomings, i.e., ineffectiveness to valorize recalcitrant organics in wastes. Considering the cost-favorability, a fermentation process can be employed to facilitate the degradation of biopolymers into smaller organics, easing the subsequent entomoremediation process. However, the efficacy of in situ fermentation was found impeded by the black soldier fly larvae (BSFL) in the current study to reduce coconut endosperm waste (CEW). Indeed, by changing into ex situ fermentation, in which the fungal Rhizopus oligosporus was permitted to execute fermentation on CEW prior to the larval feeding, the reduction of CEW was significantly enhanced. In this regard, the waste reduction index of CEW by BSFL was almost doubled as opposed to in situ fermentation, even with the inoculation of merely 0.5 wt % of Rhizopus oligosporus. Moreover, with only 0.02 wt % of fungal inoculation size to execute the ex situ fermentation on CEW, it could spur BSFL growth by about 50%. Finally, from the statistical correlation study using principal component analysis, the presence of Rhizopus oligosporus in a range of 0.5–1.0 wt % was regarded as optimum to ferment CEW via ex situ mode, prior to the valorization by BSFL in reducing the CEW.

scholarly journals Problem Faced by Precast Industry to Implement in Residential Construction

2020 ◽  
Vol 9 (5) ◽  
pp. 2394-2396
Keyword(s):  
Residential Construction ◽  
Joint Stability ◽  
Standard Size ◽  
Research Survey ◽  
Technical Issues ◽  
Storage Area ◽  
Standard Rate ◽  
The Cost ◽  
Cost Of Construction

The Precast industry is booming industry now a day, but then also the implementation ratio of precast member in residential construction work is not up to the mark. As we all know that precast having numerous advantages over the cast in situ construction method, for example it saves the total time of construction which indirectly reduces the cost of construction but still we are lagging behind in implementation of precast in it. In this research we have listed out some problem which can be cause of less implementation of precast in residential construction buildings. As discussed in paper, there are so many factors are affected on Implementation of Precast in Residential Construction Sector For example: Technical Issues and General Issues. In Technical Issues Joint stability problem during Erection, Standard size of precast element, Leakage Issues, Design change related problem, Requirement of Standard Rate per Panel, End user Profit, Additional Taxes, General Issues are: Transportation of Precast Element, Loading and Unloading problems, Transportation to sight, Storage Area, Skilled Labour Research has done and data is collected through Questionery survey, Field survey, and research survey.

Design and fabrication of polydopamine based superhydrophobic fabrics for efficient oil-water separation

Soft Matter ◽  
2021 ◽  
Author(s):  
Jixi Zhang ◽  
Ligui Zhang ◽  
Xiao Gong
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Sol Gel ◽  
High Water ◽  
Water Contact ◽  
Water Separation ◽  
Oil Water Separation ◽  
Oil Water ◽  
Fabric Surface

In this work, we prepare a PDMS-SiO2-PDA@fabric with high water contact angle (WCA=155o). Combining dopamine self-polymerization and sol-gel method, SiO2 is in situ grown on a PDA-modified fabric surface to...

Innovations of Gas Lift in Prolific, Long-perforations, and Multilayered Wells, Case Study in Sudan

2016 ◽  
Author(s):  
Xueqing Tang ◽  
Lirong Dou ◽  
Ruifeng Wang ◽  
Jie Wang ◽  
Shengbao Wang ◽  
...  
Keyword(s):  
High Water ◽  
Water Breakthrough ◽  
Start Up ◽  
Production Wells ◽  
Decline Curves ◽  
High Water Cut ◽  
Water Cut ◽  
Gas Lift

ABSTRACT Jake field, discovered in July, 2006, contains 10 oil-producing and 12 condensate gas-producing zones. The wells have high flow capacities, producing from long-perforation interval of 3,911 ft (from 4,531 to 8,442 ft). Production mechanisms include gas injection in downdip wells and traditional gas lift in updip, zonal production wells since the start-up of field in July, 2010. Following pressure depletion of oil and condensate-gas zones and water breakthrough, traditional gas-lift wells became inefficient and dead. Based on nodal analysis of entire pay zones, successful innovations in gas lift have been made since March, 2013. This paper highlights them in the following aspects: Extend end of tubing to the bottom of perforations for commingled production of oil and condensate gas zones, in order to utilize condensate gas producing from the lower zones for in-situ gas lift.Produce well stream from the casing annulus while injecting natural gas into the tubing.High-pressure nitrogen generated in-situ was used to kick off the dead wells, instead of installation of gas lift valves for unloading. After unloading process, the gas from compressors was injected down the tubing and back up the casing annulus.For previous high water-cut producers, prior to continuous gas lift, approximately 3.6 MMcf of nitrogen can be injected and soaked a couple of days for anti-water-coning.Two additional 10-in. flow lines were constructed to minimize the back pressure of surface facilities on wellhead. As a consequence, innovative gas-lift brought dead wells back on production, yielding average sustained liquid rate of 7,500 bbl/d per well. Also, the production decline curves flattened out than before.

scholarly journals Estimating impact of financial incentives on construction waste production

2018 ◽  
Vol 7 (2.13) ◽  
pp. 322
Author(s):  
Milad Pavopar
Keyword(s):  
Financial Incentives ◽  
Expanded Polystyrene ◽  
Waste Production ◽  
Materials Used ◽  
Polystyrene Waste ◽  
The Cost ◽  
Development Objectives ◽  
Project Lead ◽  
Total Price ◽  
Ready Mix Concrete

Due to destructive environmental effects of construction wastes and increasing amount of these wastes that are in conflict with sustainable development objectives, it is essential to adopt solutions in order to reduce such wastes regarding environment preservation. This study was conducted to examine impact of financial incentives on reducing construction wastes using pairwise comparisons. According to professional opinions and experience of experts in building industry based on the 7-point Likert scale, mean responses obtained to 4.93, 4.83, and 4.73 for waste materials (stone, tile, ceramic), ready mix concrete waste, and EPS (Expanded Polystyrene) waste, respectively. On the other hand, reliability of research instrument obtained at 0.77 using Cronbach’s alpha test. Moreover, it is seen that the studied materials in this research assigned 41% contribution of constructing costs to themselves; of them, fittings and tiles, ceramics and stone assigned the highest constructing cost to themselves with 12%contribution. In fact, waste of materials in projects under the “total price” contract 30-50% higher than projects under the “cost plus” contract. Increasing number of floors and area of construction project lead to average reduction in waste of materials from 4.4% to 1.4%. Change in regional price of housing will changes materials used in construction based on different prices.  

scholarly journals Terrain changes from images acquired on opportunistic flights by SfM photogrammetry

2017 ◽  
Vol 11 (2) ◽  
pp. 827-840 ◽  
Author(s):  
Luc Girod ◽  
Christopher Nuth ◽  
Andreas Kääb ◽  
Bernd Etzelmüller ◽  
Jack Kohler
Keyword(s):  
Low Cost ◽  
Rapid Change ◽  
Satellite System ◽  
Light Transport ◽  
Area Of Interest ◽  
Accuracy And Precision ◽  
Global Navigation Satellite ◽  
The Cost ◽  
Gnss Data

Abstract. Acquiring data to analyse change in topography is often a costly endeavour requiring either extensive, potentially risky, fieldwork and/or expensive equipment or commercial data. Bringing the cost down while keeping the precision and accuracy has been a focus in geoscience in recent years. Structure from motion (SfM) photogrammetric techniques are emerging as powerful tools for surveying, with modern algorithm and large computing power allowing for the production of accurate and detailed data from low-cost, informal surveys. The high spatial and temporal resolution permits the monitoring of geomorphological features undergoing relatively rapid change, such as glaciers, moraines, or landslides. We present a method that takes advantage of light-transport flights conducting other missions to opportunistically collect imagery for geomorphological analysis. We test and validate an approach in which we attach a consumer-grade camera and a simple code-based Global Navigation Satellite System (GNSS) receiver to a helicopter to collect data when the flight path covers an area of interest. Our method is based and builds upon Welty et al. (2013), showing the ability to link GNSS data to images without a complex physical or electronic link, even with imprecise camera clocks and irregular time lapses. As a proof of concept, we conducted two test surveys, in September 2014 and 2015, over the glacier Midtre Lovénbreen and its forefield, in northwestern Svalbard. We were able to derive elevation change estimates comparable to in situ mass balance stake measurements. The accuracy and precision of our DEMs allow detection and analysis of a number of processes in the proglacial area, including the presence of thermokarst and the evolution of water channels.

scholarly journals On the Theoretical CO2 Sequestration Potential of Pervious Concrete

2019 ◽  
Vol 4 (1) ◽  
pp. 12 ◽  
Author(s):  
Ethan Ellingboe ◽  
Jay Arehart ◽  
Wil Srubar
Keyword(s):  
Co2 Emissions ◽  
Co2 Sequestration ◽  
Pervious Concrete ◽  
Theoretical Formulation ◽  
Concrete Mixtures ◽  
Sequestration Potential ◽  
Carbon Dioxide Co2 ◽  
New Applications ◽  
Natural Carbonation

Pervious concrete, which has recently found new applications in buildings, is both energy- and carbon-intensive to manufacture. However, similar to normal concrete, some of the initial CO2 emissions associated with pervious concrete can be sequestered through a process known as carbonation. In this work, the theoretical formulation and application of a mathematical model for estimating the carbon dioxide (CO2) sequestration potential of pervious concrete is presented. Using principles of cement and carbonation chemistry, the model related mixture proportions of pervious concretes to their theoretical in situ CO2 sequestration potential. The model was subsequently employed in a screening life cycle assessment (LCA) to quantify the percentage of recoverable CO2 emissions—namely, the ratio of in situ sequesterable CO2 to initial cradle-to-gate CO2 emissions—for common pervious concrete mixtures. Results suggest that natural carbonation can recover up to 12% of initial CO2 emissions and that CO2 sequestration potential is maximized for pervious concrete mixtures with (i) lower water-to-cement ratios, (ii) higher compressive strengths, (iii) lower porosities, and (iv) lower hydraulic conductivities. However, LCA results elucidate that mixtures with maximum CO2 sequestration potential (i.e., mixtures with high cement contents and CO2 recoverability) emit more CO2 from a net-emissions perspective, despite their enhanced in situ CO2 sequestration potential.

Estimation of Creep-Fatigue Damage Through Indentation Test Method

2011 ◽  
Author(s):  
Raghu V. Prakash
Keyword(s):  
Tensile Properties ◽  
Fatigue Damage ◽  
Indentation Test ◽  
Creep Damage ◽  
Test Method ◽  
Specimen Preparation ◽  
Creep Fatigue ◽  
Critical Components ◽  
The Cost

Creep, creep-fatigue damage is often estimated through in-situ metallography, tensile testing of specimens. However, these methods require specimen preparation which includes specimen extraction from critical components. Automated ball indentation testing has been used as an effective tool to determine the mechanical properties of metallic materials. In this work, the tensile properties of materials subjected to controlled levels of damage in creep, creep-fatigue is studied. It is found that the tensile properties such as yield strength and UTS deteriorates with creep damage, whereas the same specimens show an improved UTS values (at the cost of ductility) when subjected to creep-fatigue interactions.

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