Development of Photocatalytic Pervious Concrete Pavement for Air and Storm Water Improvements

2012 ◽  
Vol 2290 (1) ◽  
pp. 161-167 ◽  
Author(s):  
Somayeh Asadi ◽  
Marwa M. Hassan ◽  
John T. Kevern ◽  
Tyson D. Rupnow
Keyword(s):  
Flow Rate ◽  
Mechanical Performance ◽  
Concrete Pavement ◽  
Pervious Concrete ◽  
Mix Design ◽  
Unit Weight ◽  
Experimental Program ◽  
Design Parameters ◽  
Operational Parameters ◽  
Cleaning Agents

Self-cleaning, air-purifying pervious concrete pavement is a promising technology that can be constructed with air-cleaning agents with superhydrophilic photocatalyst capabilities, such as titanium dioxide. Although this technology has the potential of supporting environment-friendly road infrastructure, its effectiveness depends on a number of design and operational parameters that need to be evaluated. The objective of this study was to evaluate the mechanical, environmental, and mix design parameters that influence the performance and effectiveness of photocatalytic pervious concrete pavement. To achieve this objective, an experimental program was conducted in which the effects of relative humidity level, pollutants' flow rate, and mix design parameters, including void ratio and depth of the photocatalytic layer, were investigated. Mechanical performance tests included porosity, unit weight, permeability, and compressive strength. The environmental efficiency of the samples to remove nitrogen oxides (NOx) from the atmosphere was measured in the laboratory. Results of the experimental program showed that increasing the depth of the photocatalytic layer increased NOx reduction efficiency. In addition, NOx removal efficiency decreased with the increase in the pollutant flow rate and increased with the increase in ultraviolet light intensity.

scholarly journals Numerical analysis of concrete-filled spiral welded stainless steel tubes subjected to compression

2018 ◽  
Author(s):  
Dongxu Li ◽  
Brian Uy ◽  
Farhad Aslani ◽  
Chao Hou
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
Finite Element Model ◽  
Mechanical Performance ◽  
Load Capacity ◽  
Element Model ◽  
Experimental Program ◽  
Design Parameters ◽  
Steel Tubes ◽  
Finite Element Software

Spiral welded stainless tubes are produced by helical welding of a continuous strip of stainless steel. Recently, concrete-filled spiral welded stainless steel tubes have found increasing application in the construction industry due to their ease of fabrication and aesthetic appeal. However, an in-depth understanding of the behaviour of this type of structure is still needed due to the lack of proper design guidance and insufficient experimental verification. In this paper, the mechanical performance of concrete-filled spiral welded stainless steel tubes will be numerically investigated with a commercial finite element software package, through which an experimental program can be designed properly. Specifically, the proposed finite element models take into account the effects of material and geometric nonlinearities. Moreover, the initial imperfections of stainless steel tubes and the form of helical welding will be appropriately included. Enhancement of the understanding of the analysis results can be achieved by extending results through a series of parametric studies based on the developed finite element model. Thus, the effects of various design parameters will be further evaluated by using the developed finite element model. Furthermore, for the purposes of wide application of such types of structure, the accuracy of the behaviour prediction in terms of ultimate strength based on current design codes will be studied. The authors herein compared the load capacity between the finite element analysis results and the existing codes of practice.

scholarly journals Long-Term Field Performance of Pervious Concrete Pavement

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Aleksandra Radlińska ◽  
Andrea Welker ◽  
Kathryn Greising ◽  
Blake Campbell ◽  
David Littlewood
Keyword(s):  
Field Performance ◽  
Concrete Pavement ◽  
Pervious Concrete ◽  
Unit Weight ◽  
Freezing And Thawing ◽  
Porous Pavement ◽  
Pavement Thickness ◽  
Multiple Samples ◽  
Term Field

The work described in this paper provides an evaluation of an aged pervious concrete pavement in the Northeastern United States to provide a better understanding of the long-lasting effects of placement techniques as well as the long-term field performance of porous pavement, specifically in areas susceptible to freezing and thawing. Multiple samples were taken from the existing pavement and were examined in terms of porosity and unit weight, compressive and splitting tensile strength, and the depth and degree of clogging. It was concluded that improper placement and curing led to uneven pavement thickness, irregular pore distribution within the pervious concrete, and highly variable strength values across the site, as well as sealed surfaces that prevented infiltration.

scholarly journals Development of a vibrationless sorting system

2021 ◽  
Vol 19 (1) ◽  
pp. e0204
Author(s):  
Selcuk Ugurluay ◽  
Ibrahim Deniz Akcali
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Separation Efficiency ◽  
Mass Movement ◽  
Seed Mass ◽  
Design Parameters ◽  
Operational Parameters ◽  
Equilibrium Angle ◽  
Sorting System

Aim of study: Size classification is essential in many industrial processes. Most classical sorting systems use vibrations as a means of classification function. In this study, a vibration-free sorting system called helical cylindrical screen has been developed against the disadvantages of vibrating systems and proposed to be used in the sorting of crop seeds.Area of study: Adana City, Turkey.Material and methods: The movement of the seed mass on the screen surface was formulated and the mass movement along the circular-helical paths was analytically expressed, leading to some operational parameters for evaluation in the screen design. By combining the mass movement parameters with effective separation conditions, an algorithm was obtained against the desired mass flow rate to determine the appropriate values of the design parameters. Experiments were performed on the machine, which was manufactured to sort peanut seeds into two different sizes, small and large.Main results: The results obtained in the experiments (separation efficiency, mass flow rate, effect of grain size on separation efficiency and equilibrium angle) were compared with the theoretical ones. The separation efficiency of the machine (99% and above) was quite good and is not affected at all by the small size ratio contained in the mixtures. The limitations of the theoretical velocities (axis and tangent) of a seed moving on the cylindrical sieve were found to be consistent with those obtained experimentally.Research highlights: The helical cylindrical sieve can be used for other particulate agricultural products with smooth surfaces such as soybeans, kidney beans, peas, etc.

Method to Investigate Mix Design Parameters of Pervious Concrete Mixtures

2016 ◽  
Vol 2577 (1) ◽  
pp. 43-52
Author(s):  
Hussein A. Kassem ◽  
Dima Z. Al Hassanieh ◽  
Maha Mrad ◽  
Ghassan R. Chehab ◽  
Majdi Abou Najm
Keyword(s):  
Pervious Concrete ◽  
Mix Design ◽  
Design Parameters ◽  
Concrete Mixtures

scholarly journals Predicting the Permeability of Pervious Concrete Based on the Beetle Antennae Search Algorithm and Random Forest Model

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Jiandong Huang ◽  
Tianhong Duan ◽  
Yi Zhang ◽  
Jiandong Liu ◽  
Jia Zhang ◽  
...  
Keyword(s):  
Random Forest ◽  
Coarse Aggregate ◽  
Functional Performance ◽  
Search Algorithm ◽  
Pervious Concrete ◽  
Mix Design ◽  
Design Parameters ◽  
Significant Variable ◽  
Correlation Parameters ◽  
Fold Cross Validation

Pervious concrete is an environmentally friendly material that improves water permeability, skid resistance, and sound absorption characteristics. Permeability is the most important functional performance for the pervious concrete while limited studies have been conducted to predict permeability based on mix-design parameters. This study proposed a method to combine the beetle antennae search (BAS) and random forest (RF) algorithm to predict the permeability of pervious concrete. Based on the 36 samples designed in the laboratory and 4 key influencing variables, the permeability of pervious concrete can be obtained by varying mix-design parameters by RF. BAS algorithm was used to tune the hyperparameters of RF, which were then verified by the so-called 10-fold cross-validation. Furthermore, the model to combine the BAS and RF was validated by the correlation parameters. The results showed that the hyperparameters of RF can be tuned by the BAS efficiently; the BAS can combine the conventional RF algorithm to construct the evolved model to predict the permeability of pervious concrete; the cement/aggregate ratio was the most significant variable to determine the permeability, followed by the coarse aggregate proportions.

scholarly journals Best practices for pervious concrete mix design and laboratory tests

2018 ◽  
Vol 11 (5) ◽  
pp. 1151-1159 ◽  
Author(s):  
F. B. P. COSTA ◽  
A. LORENZI ◽  
L. HASELBACH ◽  
L. C. P. SILVA FILHO
Keyword(s):  
Compressive Strength ◽  
Mechanical Performance ◽  
Design Method ◽  
Infiltration Rate ◽  
Pervious Concrete ◽  
Mix Design ◽  
Specimen Preparation ◽  
Test Procedures ◽  
Calculated Density ◽  
Pass Through

Abstract Pervious concrete may be used for stormwater management since it allows the water to pass through its interconnected macropores into stormwater systems or soils below. However, there is a need for additional standards related to pervious concrete prior to its widespread use, and there are many aspects related to mix design for desired properties, compaction methods, and test procedures that are not yet completely understood. These variables may significantly affect the functional and mechanical performance of the material. In this paper, mix designs and test specimen preparation techniques were evaluated. The IBRACON method for mixture design was used to obtain the mixture proportions and the calculated density for the desired porosity of 25%. In addition, two different types of specimens (cast or cored) and compaction methods (roller or Proctor hammer compacted) were performed. The density of each specimen was controlled to obtain the same calculated density. Several tests were conducted to compare the following variables: density, porosity, surface infiltration rate, permeability and compressive strength. Additionally, the effects of mortar capping versus neoprene-rubber caps on compressive strength measurements of pervious concrete were evaluated. The experimental results showed that cast specimens have more consistent results than cores. The design method studied with strict control of density was efficient to obtain the desired porosity mainly for cast specimens. The roller leads to a more compacted top surface resulting in a decrease in the infiltration rate and permeability of the cores. The mortar capping method is more consistent than the other.

Design of a continuous flow immobilized-cell reactor for biosynthetical production of L-aspartic acid

1985 ◽  
Vol 50 (10) ◽  
pp. 2122-2133 ◽  
Author(s):  
Jindřich Zahradník ◽  
Marie Fialová ◽  
Jan Škoda ◽  
Helena Škodová
Keyword(s):  
Aspartic Acid ◽  
Continuous Flow ◽  
Immobilized Cells ◽  
Scale Up ◽  
Fixed Bed ◽  
Packed Bed ◽  
Fixed Bed Reactor ◽  
Experimental Program ◽  
Design Parameters ◽  
Immobilized Cell

An experimental study was carried out aimed at establishing a data base for an optimum design of a continuous flow fixed-bed reactor for biotransformation of ammonium fumarate to L-aspartic acid catalyzed by immobilized cells of the strain Escherichia alcalescens dispar group. The experimental program included studies of the effect of reactor geometry, catalytic particle size, and packed bed arrangement on reactor hydrodynamics and on the rate of substrate conversion. An expression for the effective reaction rate was derived including the effect of mass transfer and conditions of the safe conversion-data scale-up were defined. Suggestions for the design of a pilot plant reactor (100 t/year) were formulated and decisive design parameters of such reactor were estimated for several variants of problem formulation.

scholarly journals Mortars with Recycled Aggregates from Building-Related Processes: A ‘Four-Step’ Methodological Proposal for a Review

2021 ◽  
Vol 13 (5) ◽  
pp. 2756
Author(s):  
Federica Vitale ◽  
Maurizio Nicolella
Keyword(s):  
Building Materials ◽  
Thermal Analyses ◽  
Construction Materials ◽  
Physical And Mechanical Properties ◽  
Research Trends ◽  
Mix Design ◽  
Recycled Aggregates ◽  
Design Parameters ◽  
Natural Aggregates ◽  
By Products

Because the production of aggregates for mortar and concrete is no longer sustainable, many attempts have been made to replace natural aggregates (NA) with recycled aggregates (RA) sourced from factories, recycling centers, and human activities such as construction and demolition works (C&D). This article reviews papers concerning mortars with fine RA from C&D debris, and from the by-products of the manufacturing and recycling processes of building materials. A four-step methodology based on searching, screening, clustering, and summarizing was proposed. The clustering variables were the type of aggregate, mix design parameters, tested properties, patents, and availability on the market. The number and the type of the clustering variables of each paper were analysed and compared. The results showed that the mortars were mainly characterized through their physical and mechanical properties, whereas few durability and thermal analyses were carried out. Moreover, few fine RA were sourced from the production waste of construction materials. Finally, there were no patents or products available on the market. The outcomes presented in this paper underlined the research trends that are useful to improve the knowledge on the suitability of fine RA from building-related processes in mortars.

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