Characteristics of Typical Minnesota Aggregates

1997 ◽  
Vol 1583 (1) ◽  
pp. 1-10
Author(s):  
M. Stroup-Gardiner ◽  
D. Newcomb ◽  
W. Kussman ◽  
Roger Olson
Keyword(s):  
Construction Projects ◽  
Coarse Aggregate ◽  
Fine Aggregate ◽  
Moisture Sensitivity ◽  
Air Voids ◽  
Aggregate Properties ◽  
Wide Range ◽  
Aggregate Fractions ◽  
Pass Through ◽  
Single Regression

The consensus aggregate properties recommended in SUPERPAVE and selected mixture properties were evaluated for a wide range of Minnesota aggregate sources obtained from 16 construction projects completed in 1993. Measured aggregate properties included the sand equivalent (SE) and fine aggregate angularity for the fine aggregate fractions, and percentage of fractured faces and flat and elongated particles in the coarse aggregate fractions. Laboratory-compacted samples were prepared and tested to determine air voids, voids in mineral aggregate (VMA), tensile strengths, and an assessment of the moisture sensitivity of the mixtures. Only 3 of 29 SE values for individual stockpiles were less than 40 percent. These values were not significantly affected by changes in either the general mineralogy (i.e., igneous, limestone, mixed) or the percentage passing the 0.075-mm (No. 200) sieve. Single regression analyses indicated no significant relationship between SE and either mixture moisture sensitivity or VMA. While all 25 stockpiles tested had fine aggregate angularity values greater than 40, 9 stockpiles had values below 45. It was suggested that since Minnesota aggregate gradations commonly pass through the SUPERPAVE re-stricted zone (one purpose of which is to limit the use of rounded natural sands), the minimum fine aggregate angularity value be set at 45 for all mixtures to preclude the use of 100 percent natural sands. A significant number of Minnesota coarse aggregate stockpiles have a moderate to high content of flat particles (20 to 50 percent).

scholarly journals A review on characteristics of pervious concrete using recycled aggregate

2021 ◽  
Vol 10 (1) ◽  
pp. 1-8
Author(s):  
Aaliya Navaz ◽  
Anju Paul
Keyword(s):  
Coarse Aggregate ◽  
Ground Level ◽  
Environmental Benefits ◽  
Pervious Concrete ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Concrete Compressive Strength ◽  
Coarse Aggregates ◽  
Natural Aggregates ◽  
Pass Through

Pervious concrete is a mixture of cement, coarse aggregate mixed with water. The absence of fine aggregate helps increase the voids and water can pass through these gaps and reaches to ground level. The use of recycled coarse aggregates from construction and demolition is a sustainable solution with many environmental benefits and also reduces the number of virgin aggregates to be created, hence reducing the extraction of natural resources. This paper reviews the research developments of pervious concrete by replacing natural aggregates with different percentages of recycled coarse aggregate. The papers under consideration of review have conducted to identify various properties of pervious concrete such as mechanical and hydrological properties. Keywords— pervious concrete, compressive strength, permeability

Fine-Aggregate Angularity: Automated Image Analysis Approach

2000 ◽  
Vol 1721 (1) ◽  
pp. 66-72 ◽  
Author(s):  
Eyad Masad ◽  
Joe W. Button ◽  
Tom Papagiannakis
Keyword(s):  
Image Analysis ◽  
Visual Analysis ◽  
Imaging Techniques ◽  
Permanent Deformation ◽  
Asphalt Mixtures ◽  
Automated Image Analysis ◽  
Fine Aggregate ◽  
Smoothing Effect ◽  
Aggregate Properties ◽  
Wide Range

Angularity is one of the important aggregate properties contributing to the permanent deformation resistance of asphalt mixtures. Therefore, methods that are able to rapidly and accurately describe aggregate angularity are valuable in the design process of asphalt mixtures. Two computer-automated procedures, which make use of the advances in digital-image processing, to quantify fine aggregate angularity, are presented. The first method relies on the concepts of the erosion-dilation techniques. This consists of subjecting the aggregate surface to a smoothing effect that causes the angularity elements to disappear from the image. Then, the area lost as a result of the smoothing effect is calculated and used to quantify angularity. The second method is based on the fractal approach. Image-analysis techniques are used to measure the fractal length of aggregate boundary. The fractal length increases with aggregate angularity. The proposed imaging techniques are used to capture the aggregate angularity of 23 sand samples that represent a wide range of materials. The results are compared with visual analysis and indirect methods of measuring fine-aggregate angularity, such as the uncompacted air voids, and the angle of internal friction of aggregate mass. In general, the results indicate much promise for measuring aggregate properties using automated imaging technologies.

scholarly journals ANALISIS PERBANDINGAN MUTU BETON DENGAN MENGGUNAKAN BERBAGAI CARA PENGADUKAN (READY MIX, MOLEN DAN MANUAL)

2020 ◽  
Vol 28 (1) ◽  
pp. 106
Author(s):  
Rahelina Ginting ◽  
Winarko Malau
Keyword(s):  
Compressive Strength ◽  
Construction Projects ◽  
Coarse Aggregate ◽  
Fine Aggregate ◽  
Test Results ◽  
Concrete Compressive Strength

Concrete work is widely used in construction projects now. To get a good quality concrete depends very much on the quality of the constituent materials, namely cement, water, fine aggregate, coarse aggregate, and also the process of working or stirring. In this research, 27 MPa concrete compressive strength will be investigated with various stirring methods (Manual Mix, Molen Mix and Ready Mix). These three methods of stirring certainly have their respective uses in the process, usually Manual, Molen and Ready Mix are used depending on the conditions of the project being worked on. From this test, results are obtained by means of manual stirring, Molen stirring and Ready Mix with compressive strength average: (266,467 kg / cm2) (278,368 kg / cm2) (284,595 kg / cm2). The results of the study stated that the research carried out fulfilled the estimation target 'c = 27 Mpa.

scholarly journals Influence of Coconut Fiber and Shell on Concrete

2020 ◽  
Vol 6 (8) ◽  
pp. 7-14
Keyword(s):  
Large Scale ◽  
Coarse Aggregate ◽  
Construction Material ◽  
Constructional Material ◽  
Coconut Shell ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
The People ◽  
Wide Range ◽  
Concrete Production

Concrete is a Composite material which is composed of Cement, fine aggregate, coarse aggregate binded together with a definite proportion of water. Concrete is widely used in every single construction work around the world. Due to large scale construction activities using conventional coarse aggregate such as granite as a constructional material extreme reduction in the natural stone deposit has been encountered and is affecting the environment, hence causing ecology imbalance. In current situation of construction, price factor and the wide range of extraction and processing of materialsis matter of great concern for the people as well as environment. Therefore, introduction of alternate waste material in place of natural aggregate in concrete production not only protects environment but also make concrete a suitable, economical and environment friendly construction material. Different material like Coconut Shell and Fiber can also be used alternatively. In this project Coconut Shell and fiber are used as partial replacement for coarse aggregate as well as fine aggregate, respectively. To study characteristic properties of concrete 10% and 20% for coarse aggregate and 1%, and 2% for fine aggregate are replaced by its weight with coconut shell and fiber.

Studies on effect of steel fiber and coarse aggregate on fracture properties of self compacting concrete using wedge splitting test

2019 ◽  
Vol 11 (6) ◽  
pp. 751-767
Author(s):  
Raja Rajeshwari B. ◽  
Sivakumar M.V.N.
Keyword(s):  
Fracture Energy ◽  
Coarse Aggregate ◽  
Peak Load ◽  
Mouth Opening ◽  
Test Method ◽  
Crack Mouth Opening Displacement ◽  
Fine Aggregate ◽  
Content Type ◽  
Fracture Properties ◽  
Splitting Test

Purpose Fracture properties depend on the type of material, method of testing and type of specimen. The purpose of this paper is to evaluate fracture properties by adopting a stable test method, i.e., wedge split test. Design/methodology/approach Coarse aggregate of three different sizes (20 mm, 16 mm and 12.5 mm), three ratios of coarse aggregate, fine aggregate (CA:FA) (50:50, 45:55, 40:60), presence of steel fibers, and specimens without and with guide notch were chosen as parameters of the study. Findings Load-crack mouth opening displacement curves indicate that for both fibrous and non-fibrous mixes, higher volume of aggregate and higher size of coarse aggregate have high fracture energy. Originality/value For all volumes of coarse aggregate, it was noticed that specimens with 12.5 mm aggregate size achieved highest peak load and abrupt drop post-peak. The decrease in coarseness of internal structure of concrete (λ) resulted in the increase of fracture energy.

Managing integration in infrastructure alliance projects

2017 ◽  
Vol 10 (1) ◽  
pp. 5-31 ◽  
Author(s):  
Anna-Maija Hietajärvi ◽  
Kirsi Aaltonen ◽  
Harri Haapasalo
Keyword(s):  
Construction Projects ◽  
Research Approach ◽  
Content Type ◽  
Complex Projects ◽  
Wide Range ◽  
Project Organizations ◽  
Integration Mechanisms ◽  
Organizational Integration ◽  
Time Critical

Purpose The effective management of inter-organizational integration is central to complex projects. Such projects pose significant challenges for integration, as organizations struggle with constantly changing inter-organizational interdependencies and must develop and adapt integration mechanisms to meet new demands. The purpose of this paper is to understand what kinds of integration mechanisms are used and how they are developed and adjusted during the infrastructure alliance projects. Design/methodology/approach This study provides empirical evidence of integration dynamics in project alliancing by analyzing two infrastructure alliance projects – a complex tunnel construction project and a railway renovation project. The research approach is an inductive case study. Findings This paper identifies integration mechanisms adopted in two case projects and three central triggers that led to changes in the integration mechanisms: project lifecycle phase, unexpected events and project team’s learning during the project. Practical implications Integration capability should be a precondition for alliance project organizations and requires the adoption of a wide range of integration mechanisms, as well as an ability to adjust those mechanisms in response to everyday dynamics and emergent situations. Originality/value Although unplanned contingencies and the responses to them represent important influences in organizations, there is limited amount of research on the dynamics of integration. The findings will be of value in supporting the management of inter-organizational integration in complex, uncertain and time-critical construction projects.

scholarly journals Infection Prevention Time Required for Construction and Design at a Large Tertiary-Care Hospital, 2019

2020 ◽  
Vol 41 (S1) ◽  
pp. s69-s70
Author(s):  
Angie Dains ◽  
Michael Edmond ◽  
Daniel Diekema ◽  
Stephanie Holley ◽  
Oluchi Abosi ◽  
...  
Keyword(s):  
Infection Control ◽  
Patient Care ◽  
Construction Projects ◽  
Small Scale ◽  
Care Hospital ◽  
Class Iii ◽  
Construction Sites ◽  
Wide Range ◽  
Time Required ◽  
Class Iv

Background: Including infection preventionists (IPs) in hospital design, construction, and renovation projects is important. According to the Joint Commission, “Infection control oversights during building design or renovations commonly result in regulatory problems, millions lost and even patient deaths.” We evaluated the number of active major construction projects at our 800-bed hospital with 6.0 IP FTEs and the IP time required for oversight. Methods: We reviewed construction records from October 2018 through October 2019. We classified projects as active if any construction occurred during the study period. We describe the types of projects: inpatient, outpatient, non–patient care, and the potential impact to patient health through infection control risk assessments (ICRA). ICRAs were classified as class I (non–patient-care area and minimal construction activity), class II (patients are not likely to be in the area and work is small scale), class III (patient care area and work requires demolition that generates dust), and class IV (any area requiring environmental precautions). We calculated the time spent visiting construction sites and in design meetings. Results: During October 2018–October 2019, there were 51 active construction projects with an average of 15 active sites per week. These sites included a wide range of projects from a new bone marrow transplant unit, labor and delivery expansion and renovation, space conversion to an inpatient unit to a project for multiple air handler replacements. All 51 projects were classified as class III or class IV. We visited, on average, 4 construction sites each week for 30 minutes per site, leaving 11 sites unobserved due to time constraints. We spent an average of 120 minutes weekly, but 450 minutes would have been required to observe all 15 sites. Yearly, the required hours to observe these active construction sites once weekly would be 390 hours. In addition to the observational hours, 124 hours were spent in design meetings alone, not considering the preparation time and follow-up required for these meetings. Conclusions: In a large academic medical center, IPs had time available to visit only a quarter of active projects on an ongoing basis. Increasing dedicated IP time in construction projects is essential to mitigating infection control risks in large hospitals.Funding: NoneDisclosures: None

Characteristics of Wear Layered Laston Mix Using Waste Concrete Aggregate

2021 ◽  
Vol 3 (3) ◽  
pp. 459-468
Author(s):  
Yanti ◽  
Rais Rachman ◽  
Alpius
Keyword(s):  
Coarse Aggregate ◽  
Mixture Design ◽  
Concrete Aggregate ◽  
Fine Aggregate ◽  
Waste Concrete ◽  
Characteristic Value ◽  
Marshall Test ◽  
Pavement Material

The research objective focuses on testing the characteristics of the Laston Lapis Aus mixture, the aggregate taken later to be studied is the aggregate of Concrete Waste. The method used in this study included testing the properties of coarse aggregate, fine aggregate and filler, after that the Laston Lapis Aus mixture design was carried out after that the marshall test was carried out while the marshalltest was carried out namely the conventional marshall to get the characteristic value. The results showed that the characteristics of the pavement material in the form of aggregates from Concrete Waste tested the 2018 Bina Marga General Specifications as road layers. Through Marshall testing, the characteristics of the Laston Lapis Aus mixture were abtained with asphalt levels of 5,50%, 6,00%, 6,50%, 7,00%, and 7,50%.

Performance of a Near Shore Oscillating Wave Surge Converter With Variable Flap Configurations in Various Sea Conditions

2021 ◽  
Author(s):  
Landon Sugar ◽  
Faete Filho ◽  
Tarek Abdel-Salam ◽  
Michael Muglia ◽  
Kurabachew Duba
Keyword(s):  
Wave Energy ◽  
Structural Integrity ◽  
Specific Reference ◽  
Wave Forces ◽  
Extreme Wave ◽  
Wide Range ◽  
Near Shore ◽  
Wave States ◽  
Pass Through ◽  
Survival Mode

Abstract Oscillating Wave Surge Converters (OWSCs) are designed to enter survival mode during extreme wave conditions where they forego the opportunity to extract energy to preserve structural integrity. While this is a good tradeoff, it is important that OWSC technology progresses to a point where energy is constantly extracted as long as waves are present. This work addresses the need for an OWSC that can extract wave energy in a wide range of sea conditions while minimizing structural overloading by regulating the fluid-structure interaction. The OWSC being studied here was conceptually designed and patented by researchers at NREL. It consists of a flap face that resembles household blinds, where the flaps can be opened or closed to accommodate the sea conditions. The performance of this variable geometry OWSC in various, shallow wave states was studied in two numerical modeling programs. Of particular interest were the flap’s hydrodynamic coefficients and potential power generation at a specific reference site. This configuration was predicted to mitigate wave forces by allowing some of the wave energy to pass through the device, thus preserving its structural integrity.

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