scholarly journals Comparison of standards and requirements for porous asphalt mixtures

2021 ◽  
Author(s):  
Iva Brkić ◽  
Aleksandra Deluka-Tibljaš ◽  
Marijana Cuculić ◽  
Ivana Pranjić
Keyword(s):  
Scientific Literature ◽  
Asphalt Mixtures ◽  
National Standards ◽  
The Other ◽  
Air Voids ◽  
Porous Asphalt ◽  
Abrasion Loss ◽  
The Us ◽  
Comparison Of Standards ◽  
Very High

Porous asphalt is a bituminous material prepared in such a manner that it has a very high content of interconnected voids that allow passage of water and air in order to provide the compacted mixture with better drainage and noise reducing characteristic. The analysis of available regulations and scientific literature shows that the national standards of porous asphalt mixtures differ in type of granulometric envelopes, the type of bitumen and its content in the mixture and the limits of the air voids content in the mixture. In this paper, standards used for porous asphalt in Croatia are compared with the US, Australian and Dutch standards for this type of asphalt. In addition, samples prepared based on HRN EN 13108-7 and HRN EN 12697-17 requirements were tested and results were compared using Croatian and other available standards. This paper also investigates the effects of ambient temperature on abrasion loss of porous asphalt. The abrasion loss results are compared to the other standards.

scholarly journals Performance and Durability of Porous Asphalt Mixtures Manufactured Exclusively with Electric Steel Slags

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3306 ◽  
Author(s):  
Marta Skaf ◽  
Emiliano Pasquini ◽  
Víctor Revilla-Cuesta ◽  
Vanesa Ortega-López
Keyword(s):  
Mechanical Performance ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Electric Steelmaking ◽  
Porous Asphalt ◽  
Bituminous Mixtures ◽  
Abrasion Loss ◽  
Water Sensitivity ◽  
Electric Arc Furnace Slag ◽  
Furnace Slag

Electric arc furnace slag (EAFS) and ladle furnace slag (LFS) are by-products of the electric steelmaking sector with suitable properties for use in bituminous mixtures as both coarse and fine aggregates, respectively. In this research, the production of a porous asphalt mixture with an aggregate skeleton consisting exclusively of electric steelmaking slags (using neither natural aggregates nor fillers) is explored. The test program examines the asphalt mixtures in terms of their mechanical performance (abrasion loss and indirect tensile strength), durability (cold abrasion loss, aging, and long-term behavior), water sensitivity, skid and rutting resistance, and permeability. The results of the slag-mixes are compared with a standard mix, manufactured with siliceous aggregates and cement as filler. The porous mixes manufactured with the slags provided similar results to the conventional standard mixtures. Some issues were noted in relation to compaction difficulties and the higher void contents of the slag mixtures, which reduced their resistance to raveling. Other features linked to permeability and skid resistance were largely improved, suggesting that these mixtures are especially suitable for permeable pavements in rainy regions. In conclusion, a porous asphalt mixture was produced with 100% slag aggregates that met current standards for long-lasting and environmentally friendly mixtures.

EXPERIMENTAL EVALUATION OF ANTI-STRIPPING ADDITIVES ON POROUS ASPHALT MIXTURES

2016 ◽  
Vol 78 (7-2) ◽  
Author(s):  
Nurul Athma Mohd Shukry ◽  
Norhidayah Abdul Hassan ◽  
Mohd Rosli Hainin ◽  
Mohd Ezree Abdullah ◽  
Nor Asniza Mohamed Abdullah ◽  
...  
Keyword(s):  
Resilient Modulus ◽  
Asphalt Mixture ◽  
Hydrated Lime ◽  
Modified Bitumen ◽  
Air Voids ◽  
Porous Asphalt ◽  
Abrasion Loss ◽  
Asphalt Mix ◽  
Strength And Durability ◽  
Permeability Rate

The open structure of porous asphalt mix influences its strength and durability against air, water and clogging materials. These factors cause loss of adhesion between binder-aggregate interface and loss of cohesion within the binder film.  This could lead to stripping problem which contribute to premature failures as well as deterioration in the performance and service life of porous asphalt. Therefore, this study is aimed to evaluate the potential of diatomite as anti-stripping additives in porous asphalt and compared with hydrated lime and Ordinary Portland Cement (OPC). Field Emission Scanning Electron Microscopy (SEM) test and Energy Dispersive X-ray Spectroscopy analysis (EDX) were conducted to investigate the microstructure and chemical composition of the anti-stripping additives. A number of gyratory compacted samples of porous asphalt mixture with Malaysian gradation were prepared. Each sample was incorporated with 2% of anti-stripping additives as filler then mixed with polymer modified bitumen of PG76. The samples were measured for air voids content, permeability rate, resilient modulus and abrasion loss. The results indicate that samples prepared with hydrated lime show higher permeability rate and lower abrasion loss compared to samples with OPC and diatomite. However, the samples prepared with diatomite show enhanced resilient modulus compared to those with hydrated lime and OPC.

Resistance to Permanent Deformation and Low-Temperature Cracking of Porous Asphalt Mixture Using the Tafpack Super Additive

2009 ◽  
Vol 620-622 ◽  
pp. 347-250 ◽  
Author(s):  
Ting Wei Cao ◽  
Shao Peng Wu ◽  
Ming Yu Chen ◽  
Jun Tao Lin
Keyword(s):  
Low Temperature ◽  
Permanent Deformation ◽  
Asphalt Mixture ◽  
Asphalt Mixtures ◽  
Service Temperature ◽  
Air Voids ◽  
Porous Asphalt ◽  
Three Point Bending ◽  
Uniaxial Creep ◽  
Low Temperature Cracking

Porous asphalt is one of the most functional structures for the surface layer of asphalt pavement, which has already shown excellent noise reduction property for its 20% air voids in the structure. However, mechanical degradation is also monitored because of the high air voids, for example, permanent deformation in high service temperature and cracking in low service temperature. The Tafpack Super (TPS) additive was used in this study and expected to improve the resistance to permanent deformation and low-temperature cracking of porous asphalt mixture. Unconfined static uniaxial creep test and three-point bending test were conducted to study the effects of TPS additive on the permanent deformation and anti-cracking property of porous asphalt mixture, respectively. Experimental results showed that the TPS additive decreased the creep deformation and increased the creep stiffness modulus in uniaxial creep test. TPS additive had little effect on the brittleness temperature porous asphalt mixtures as shown in three-point bending testing. However, the flexural strength-strain response curve indicated that with the increase of TPS additive, porous asphalt mixtures exhibited better resistance to cracking. Porous asphalt mixtures with TPS additive indicate excellent temperature susceptibility and can be applied to a wider field of road engineering.

A Comparative Study of Anti-Stripping Additives in Porous Asphalt Mixtures

2014 ◽  
Vol 70 (7) ◽  
Author(s):  
Mohamad Yusri Aman ◽  
Zulkurnain Shahadan ◽  
Mohd Zaime Mat Noh
Keyword(s):  
Asphalt Mixtures ◽  
Cohesive Failure ◽  
Moisture Sensitivity ◽  
Asphalt Mixes ◽  
Air Voids ◽  
Porous Asphalt ◽  
Coefficient Of Permeability ◽  
Indirect Tensile ◽  
Aashto T283 ◽  
Quarry Dust

Presence of water in porous asphalt mixtures detrimentally affected the bonding between binder-aggregate interface and cohesive failure within the binder-filler mastic, making them prone to stripping which contribute to the performance and durability. This paper presents the effect of anti-stripping additives in porous asphalt mixes. In this study, the Marshall specimens were prepared using quarry dust, ordinary Portland Cement (OPC) and Pavement Modifier (PMD) as filler then mixed with 60/70 penetration grade bitumen. The specimens were measured for air voids content and coefficient of permeability and subsequently tested using indirect tensile and Cantabro tests. The moisture sensitivity of porous asphalt was determined based on the ratio of dry and conditioned specimens according to AASHTO T283. The specimens prepared with PMD showed lower air voids content, hence decrease the permeability to give a higher tensile strength and lower abrasion loss compared to specimens prepared with OPC and quarry dust. Based on the results, the PMD filler has a great potential to improve resistance to moisture damage compared to mixes with OPC and specimens prepared with quarry dust fillers.

scholarly journals Effect of Synthetic Fibers and Hydrated Lime in Porous Asphalt Mixture Using Multi-Criteria Decision-Making Techniques

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 675 ◽  
Author(s):  
Carlos J. Slebi-Acevedo ◽  
Pedro Lastra-González ◽  
Miguel A. Calzada-Pérez ◽  
Daniel Castro-Fresno
Keyword(s):  
Decision Making ◽  
Optimization Problem ◽  
Hydrated Lime ◽  
Binder Content ◽  
Asphalt Mixtures ◽  
Multi Criteria Decision Making ◽  
Multiple Responses ◽  
Air Voids ◽  
Porous Asphalt ◽  
Particle Loss

Porous asphalt is a type of mixture characterized by having high air void percentages that offers multiple benefits when used in wearing courses in terms of driving safety, water flow management, and noise reduction. However, the durability of porous asphalt (PA) mixtures is significantly shorter when compared to dense-graded asphalt mixtures. This study investigated the impact of polyolefin–aramid fibers and hydrated lime in the functional and mechanical performance of porous asphalt mixtures. A parametric study based on the concept of design of experiments was carried out through the Taguchi methodology. Accordingly, an experimental design was conducted based on the L18 full factorial orthogonal array. Three control factors—fiber content, binder content, and filler type—were included at various levels, and multiple responses including total air voids, interconnected air voids, particle loss in dry conditions, particle loss in wet conditions, and binder drainage were assessed experimentally. Signal-to-noise ratios were calculated to determine the optimal solution levels for each control factor for the multiple responses. In the second phase of the research, multi-criteria decision-making techniques—namely, criteria importance through inter-criteria correlation and weighted aggregated sum product assessment—were used to transform the multiple-response optimization problem into a single-unique optimization problem and to elaborate a preference ranking among all the mixture designs. The most significant levels for acquiring the optimum overall response value were found to be 0.05% for fiber content and 5.00% for binder content and mixed filler with hydrated lime.

scholarly journals Virtual Asphalt to Predict Roads’ Air Voids and Hydraulic Conductivity

2018 ◽  
Author(s):  
Mustafa Aboufoul ◽  
Andrea Chiarelli ◽  
Isaac Triguero ◽  
Alvaro Garcia
Keyword(s):  
Hydraulic Conductivity ◽  
Asphalt Mixtures ◽  
Maximum Aggregate Size ◽  
High Dispersion ◽  
Void Content ◽  
Air Voids ◽  
Porous Asphalt ◽  
Pore Networks ◽  
Asphalt Materials ◽  
Air Void

This paper investigates the effects of air void topology on hydraulic conductivity in asphalt mixtures with porosity in the range 14%-31%. Virtual asphalt pore networks were generated using the Intersected Stacked Air voids (ISA) method, with its parameters being automatically adjusted by the means of a differential evolution optimisation algorithm, and then 3D printed using transparent resin. Permeability tests were conducted on the resin samples to understand the effects of pore topology on hydraulic conductivity. Moreover, the pore networks generated virtually were compared to real asphalt pore networks captured via X-ray Computed Tomography (CT) scans. The optimised ISA method was able to generate realistic 3D pore networks corresponding to those seen in asphalt mixtures in term of visual, topological, statistical and air void shape properties. It was found that, in the range of porous asphalt materials investigated in this research, the high dispersion in hydraulic conductivity at constant air void content is a function of the average air void diameter. Finally, the relationship between average void diameter and the maximum aggregate size and gradation in porous asphalt materials was investigated.

scholarly journals Effects of Crumb Rubber Size and Concentration on Performance of Porous Asphalt Mixtures

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Altan Cetin
Keyword(s):  
Large Scale ◽  
Resilient Modulus ◽  
Asphalt Mixture ◽  
Crumb Rubber ◽  
Asphalt Mixtures ◽  
Performance Characteristics ◽  
Moisture Susceptibility ◽  
Porous Asphalt ◽  
Dry Process ◽  
Abrasion Loss

The purpose of this study is to investigate the effect of size distribution and concentration of crumb rubber on the performance characteristics of porous asphalt mixture. The recycling of scrap tires in asphalt pavements appears as an important alternative providing a large-scale market. The characteristics of bitumen are very important with regard to service life of porous asphalt pavement. The experimental study consists of two main steps. Firstly, the mixture design was performed to determine the optimum bitumen content. In the latter step, the mixtures were modified by dry process using crumb rubber in three different grain size distributions of #4~#20, #20~#200, and #4~#200 and rubber content of 10%, 15%, and 20% as weight of optimum bitumen. The permeability, Cantabro abrasion loss, indirect tensile strength, moisture susceptibility, and resilient modulus tests were carried out on the specimens. Test results show that #20~#200 sized rubber particles reduced air voids and coefficient of permeability, while they increased the Cantabro abrasion loss. In general, increasing the crumb rubber size and content decreased the performance characteristics of the porous asphalt mixtures.

Thrombotic Thrombocytopenic Purpura: Mechanism for Effectiveness of Plasmapheresis

1979 ◽  
Author(s):  
J. G. Kelton ◽  
P. B. Neame ◽  
I. Walker ◽  
A. G. Turpie ◽  
J. McBride ◽  
...  
Keyword(s):  
Platelet Count ◽  
Thrombotic Thrombocytopenic Purpura ◽  
The Other ◽  
Unknown Etiology ◽  
Normal Range ◽  
Antiplatelet Antibody ◽  
Thrombocytopenic Purpura ◽  
Serious Illness ◽  
Normal Platelet ◽  
Very High

Thrombotic thrombocytopenic purpura (TTP) is a rare but serious illness of unknown etiology. Treatment by plasmapheresis has been reported to be effective but the mechanism for benefit is unknown. We have investigated the effect of plasmapheresis in 2 patients with TTP by quantitating platelet associated IgG (PAIgG) levels prior to and following plasmapheresis. Both patients had very high levels of PAIgG at presentation (90 and A8 fg IgG/platelet respectively, normal 0-5). in both, the PAIgG levels progressively fell to within the normal range and the platelet count rose following plasmapheresis. One patient remained in remission with normal platelet counts and PAIgG levels. The other relapsed after plasmapheresis and the PAIgG level rose prior to the fall in platelet count. Plasmapheresis was repeated and resulted in normalization of both the platelet count and PAIgG level. It is suggested that plasmapheresis removes antiplatelet antibody or immune complexes which may be of etiological importance in this illness.

Growth Characteristics of Activated Sludges Acclimated to para-Nitrophenol in Batch and Continuous Modes

1994 ◽  
Vol 29 (7) ◽  
pp. 327-333
Author(s):  
Y. Matsui ◽  
F. Yamaguchi ◽  
Y. Suwa ◽  
Y. Urushigawa
Keyword(s):  
Growth Characteristics ◽  
The Other ◽  
Operational Mode ◽  
Continuous Mode ◽  
Relative Resistance ◽  
Batch Mode ◽  
The Given ◽  
Operational Modes ◽  
Very High ◽  
Sensitive Group

Activated sludges were acclimated to p-nitrophenol (PNP) in two operational modes, a batch and a continuous. The operational mode of the PNP acclimation of activated sludges strongly affected the physiological characteristics of predominant microorganisms responsible for PNP degradation. Predominant PNP degraders in the sludge in batch mode (Sludge B) had lower PNP affinity and were relatively insensitive to PNP concentration. Those of the sludge in continuous mode (Sludge C), on the other hand, had very high PNP affinity and were sensitive to PNP. MPN enumeration of PNP degraders in sludge B and C using media with different PNP concentrations (0.05, 0.2,0.5 and 2.0 mM) supported the above results. Medium with 0.2 mM of PNP did not recover PNP degraders in sludge C well, while it recovered PNP degraders in sludge B as well as the medium with 0.05 mM did. When switching from one operational mode to the other, the predominant population in sludge B shifted to the sensitive group, but that of sludge C did not shift at the given loading of PNP, showing relative resistance to inhibitive concentration.

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