scholarly journals Effect of percent air voids content on the deformation properties of the asphalt mixture

2021 ◽  
Vol 1209 (1) ◽  
pp. 012078
Author(s):  
J Bokomlasko ◽  
J Mandula

Abstract Asphalt mixture is a building material with many advantages. Therefore, it is most used in road construction. If the asphalt mixture is laid with the prescribed technology, it can withstand load effects to long-term. It is necessary to take samples that will be subjected to laboratory measurements. There are several laboratory test, for example measurement thickness of the asphalt mixture layers, the aggregate fraction, quantity of binder in the mixture, determination of air void in asphalt mixture layers. Samples taken directly from the construction site are subjected to laboratory tests. This article focuses on one of the laboratory tests and it is determination of air void in asphalt mixture layers. The determination of air void in asphalt mixture layers is test in detail, because this effect has influence on the deformation properties of asphalt mixture layers. Therefore, it was necessary to model of air void in asphalt mixture layers with different degrees air void. On this purpose was use program Abaqus. The results were plotted. This graphs showed that increasing the air void in asphalt mixture layers has effect on the expansion of deformations. This can lead to faster pavement degradation.

2020 ◽  
Vol 12 (7) ◽  
pp. 2966 ◽  
Author(s):  
Chao Chai ◽  
Yong-Chun Cheng ◽  
Yuwei Zhang ◽  
Yu Chen ◽  
Bing Zhu

This paper focuses on the freeze-thaw cycles (F-T cycles) resistance of porous asphalt mixture (PAM) with different air voids in order to explore the gradation of the PAM suitable for seasonal freezing regions. Three sets of PAMs with 18%, 21%, and 25% air voids were designed. After 0–20 F-T cycles, the effects of F-T cycles on the performance degradation of three groups of PAMs were studied by performing a low-temperature splitting test with acoustic emission technology, a normal temperature splitting test, a compression test, a Cantabro particle loss test, and a dynamic creep test. The results show that the damage process of PAM caused by multiple F-T cycles could be more clearly defined by acoustic emission parameters. In addition, the larger the air void, the smaller its indirect tensile strength and compression strength, and the worse its particle loss resistance and high-temperature stability, which made the adverse effect of F-T cycles more significant. Therefore, the air void of PAM used in seasonal freezing regions is suggested to be less than 21%.


2012 ◽  
Vol 486 ◽  
pp. 378-383 ◽  
Author(s):  
Che Wan Che Norazman ◽  
Ramadhansyah Putra Jaya ◽  
Meor Othman Hamzah

Oven ageing is a set of procedure to simulate the accelerated effects of ageing on pavements structures. In this study, the effect of long-term oven ageing on porous asphalt mixture made with SBS modified binder was investigated. The resilient modulus, water permeability and air voids test results were the performance indicators used to evaluate the effects of ageing. The test results showed that, the resilient modulus of long term aged specimens was higher than those of unaged specimens. From the permeability test results, unaged SBS mixes exhibit lower coefficient permeability compared to the corresponding long-term oven age specimens. Most likely, ageing caused binder hardening, making the mix more difficult to compact and hence exhibited more continuous voids which in turn lead to higher permeability. In addition, the coefficient of permeability decreases as the binder content increased.


2019 ◽  
Vol 9 (19) ◽  
pp. 4126
Author(s):  
Guangji Xu ◽  
Xiao Chen ◽  
Xiaoming Huang ◽  
Tao Ma ◽  
Wei Zhou

The air voids distribution has a significant effect on the pavement performance related distresses such as rutting, cracking, moisture damage and permeability. However, most studies only quantified the air voids by average content, ignoring the heterogeneity inside the materials. This study focuses on the heterogeneity of air voids distribution inside the open-grade asphalt mixture based on 2D image analysis. Equivalent aperture is proposed to measure the area of each air void. Results showed that along both vertical and horizontal sections inside the open-grade asphalt mixture, the number of voids with 0~2 mm equivalent aperture would have a great impact on the total number of voids, while large amounts of small voids would not significantly affect the total voids number. Additionally, voids with 0~4 mm equivalent aperture account for the largest proportion, and when the equivalent aperture is beyond 4 mm, the number of voids would decrease as the equivalent aperture increases, regardless of the void areas. Furthermore, in both vertical and horizontal sections, as the equivalent aperture increases, the speed to accumulate voids area would firstly increase and then decrease. As the equivalent aperture increases, the contribution to the total voids area would increase accordingly, and it would approach the peak when the equivalent aperture reaches about 8 mm.


2014 ◽  
Vol 12 (1) ◽  
Author(s):  
Candra Putra Kiswara ◽  
Andi Saiful Amal

STUDI PERILAKU CAMPURAN LATASTON (HRS-WC) DENGAN“LIMBAH KARET BAN LUAR” SEBAGAI BAHAN PENGGANTISEBAGIAN ASPALCandra Putra Kiswara 1& Andi Saiful A21&2Jurusan Teknik Sipil Fakultas Teknik Universitas Muhammadiyah MalangAlamat korespondensi : Jalan Raya Tlogomas 246 Malang 65144e-mail: [email protected], [email protected] to be one of the problems facing the nation at this time. Community is very disturbed bythe presence of various types of waste that is around their neighborhood. Ranging from industrialwaste to the waste home.The basic requirements of a road construction is to prepare the surface layer of a flat andstrong to ensure high security for a long time and the preservation of every detail in a variety ofweather. It required an asphalt mixture that is capable of supporting loads as well as capture thedamaging effects of traffic and the weather (climate) and can provide good service.With the addition of waste tire rubber is significantly affect mixture properties such Lataston(HRS-WC) Stability, Marshall Quontient, Flow and Air Voids. This is evidenced by the results oftesting using a Marshall. The average value of stability the average of 1220 kg. For Lataston (HRSWC)mix with additives outer tire rubber to rubber optimum levels (KKO) 11,50%, to produce amixture of qualities: Marshall Stability value = 1220 kg, Marshall Quotient value = 7,2 kN / mm,Value Air Marshall voids = 10,00%, Value Bitumen film thickness = 5,6 mm.Key Word: Waste Tire Rubber, Marshall Caracteristic


Author(s):  
Gale C. Page ◽  
James A. Musselman ◽  
David C. Romano

In an effort to further improve the rut resistance of asphalt pavements in Florida, the Florida Department of Transportation implemented specifications requiring that the production of asphalt mixes be stopped when the air-void content falls below a critical level. To address the problem of low air voids and rutting in north Florida, a proposal was made to reduce the maximum amount of material allowed to pass the 75-μm sieve (P-75μm) at design for asphalt mixtures containing north Florida limestone aggregates. A field study was then undertaken to determine whether this proposal would adequately resolve the problem of low air voids during production due to high P-75μm. The purpose of the study was to determine the amount of degradation to a typical north Florida limestone material and the subsequent effects that degradation has on air voids. The results indicate that although the north Florida limestone aggregates used in this study did degrade significantly, the asphalt contractor was, in general, able to control the amount of P-75μm material in the mix by wasting the baghouse fines. During production, the air voids were low on a number of samples. The source of these low air voids appears to be related to a combination of a high asphalt content in the mix as well as a high P-75μm content. The findings do not support the proposal to reduce the P-75μm content at design at this time. An unexpected finding of this study was that the bulk specific gravities of the commercial aggregate products were less than expected. The impact of this finding is that the voids in the mineral aggregate (VMA) of the mix at design would not meet minimum specification requirements. Although this could make it difficult for an asphalt mixture to have adequate air voids during production, the primary impact of a low VMA is that the pavement would have poor durability and would potentially become brittle and crack prematurely.


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7614
Author(s):  
Łukasz Anaszewicz

This article presents the results of research on the effect of plasticisers made based on four different compounds—melamine (M), naphthalene (NF), acrylic polymers (AP) and polycarboxylic ethers (PC)—added to the tested mixes in the amount of 2% of the fly ash (FA). The influence of superplasticisers (SPs) on the consistency of the fresh concrete was investigated using a flow table and a penetrometer, and the air voids content was determined by means of a porosimeter. Additionally, the influence of plasticisers on the viscosity of the paste was investigated using a rheometer. Hardened mortar that matured under two different conditions was also tested at elevated and room temperatures. The tested properties were 7-, 28- and 90-days compressive strength and internal microstructure viewed under a microscope. NF had the greatest viscosity-reducing effect while it increased the air void volume in the mix at the same time. The highest early and late strengths were obtained after curing in elevated temperature samples with an acrylic-polymer-based superplasticiser. However, the increased curing temperature of the samples only influenced the early strength results. Its effect was not visible after 90 days. The AP addition also had a significant impact on improving the consistency of the mixture. The addition of plasticisers did not affect the microstructure of the specimens.


2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Jiantong Zhang ◽  
Jun Yang ◽  
Tiejun Liu ◽  
Rongxing Cai ◽  
Rui Yang

The purpose of this paper is to obtain the pore distribution of asphalt mixture accurately by nondestructive technology. Specimens prepared with four gradations of asphalt mixtures were scanned using X-ray computed tomography (CT) which was used to measure air void sizes at different depths within specimens. The air void distributions of obtained CT images were analyzed using ring blocking segmentation combining Otsu’s method, which provided an accurate estimate of air voids in asphalt mixtures. The image processing results showed that air void distribution was not uniform in the specimens; higher air void concentrations were found at the top and bottom of the specimen, and lower, in the rest of the sample depth. The air void sizes of SUP13 and AC13 are mainly distributed between 0.15 to 0.2 mm, while PA13 and SMA13 are 0.4 to 0.65 mm and 0.4 to 0.7 mm, respectively. It is believed that the CT pictures processed by the ring blocking segmentation combining Otsu’s method is feasible and rational to capture the air voids size and content of asphalt mixtures.+


1984 ◽  
Vol 21 (1) ◽  
pp. 147-165 ◽  
Author(s):  
K. Y. Lo ◽  
B. Lukajic

The C.W. Intake Tunnel of the Darlington Nuclear Station is D-shaped in section with a span of 8 m and a length of 925 m beneath Lake Ontario. The tunnel is located in a horizontally bedded limestone with variable shaly interbeds.The geotechnical investigation including in-situ rock stress measurements, and laboratory determination of strength and deformation properties as well as time-dependent behaviour are reported. Design of the tunnel, in particular provisions for "rock squeeze," is described in detail.To verify the design approach adopted and the provisions made, field instrumentation was performed during excavation of the tunnel. The results of field measurements of stresses and displacements were compared with premonitoring analysis. Postmonitoring analyses were also performed using the as-constructed condition. It is shown that the performance of the tunnel is in general agreement with the predicted behaviour in both short and long term conditions. Keywords: stress, displacement, time-dependent deformation, stressmeter, tunnel, rock mechanics, rock squeeze.


Respuestas ◽  
2016 ◽  
Vol 21 (1) ◽  
pp. 108
Author(s):  
Carlos Hernando Higuera-Sandoval

Objetivo: El presente artículo muestra de manera detallada el efecto de la temperatura en la determinación del módulo dinámico del cemento asfáltico y el módulo dinámico de la mezcla asfáltica. Metodología: Para la investigación se consideraron las temperaturas medias anuales ponderadas más representativas de las regiones del departamento de Boyacá de 13°C a 20°C, también la velocidad de operación de sus carreteras de 30, 50, 70 y 100 Km/hora y se analizaron dos cementos asfálticos del tipo AC 60 – 70 y AC 80 – 100, estipulados en el artículo INV 400-13 de las especificaciones generales de construcción de carreteras del Instituto Nacional de Vías – INVIAS - 2013 y que son de uso frecuente en la construcción de pavimentos en el departamento de Boyacá. Para la determinación de los módulos dinámicos del asfalto y de la mezcla asfáltica se siguió la metodología de la SHELL y se analizaron las variables como la temperatura media anual ponderada del aire – TMAP, la temperatura de trabajo de la mezclas – tmix, la velocidad de operación de las carreteras – Vop, el tiempo de aplicación de la carga – t, la frecuencia de la aplicación de la carga – F y el índice de penetración del asfalto – IP. Resultados: Se presentan los módulos dinámicos del asfalto y de la mezcla asfáltica para diferentes temperaturas medias anuales ponderadas y diferentes velocidades de operación de las carreteras del Departamento de Boyacá, para los asfaltos tipo AC 60-70 y AC 80-100. Conclusión: El aporte de este trabajo de investigación es de gran utilidad para los ingenieros de diseño de estructuras de pavimentos, porque permite conocer el módulo dinámico de una mezcla asfáltica densa en caliente tipo INVIAS MDC-19 para rodadura, teniendo en cuenta la temperatura media anual ponderada de la zona del proyecto y las características de operación de la carretera, variables fundamentales para el diseño de las estructuras de pavimento flexible.Abstract Objective: This article shows in detail the effect of temperature on the determination of the dynamic module of asphaltic cement and the dynamic module of the asphalt mix. Method: Average pondered annual temperatures of the most representative Regions of the department of Boyaca ranging 13 ° C to 20 ° C were considered, as well as the speed of operation of its highways 30, 50, 70 and 100 km / hour and were considered, and two asphalt cements the type AC 60 - 70 and AC 80 – 100 which are stipulated in the article INV 400-13 of the general speciications for road construction of the National roads Institute - INVIAS - 2013 of frequent use in the pavement construction in the department of Boyaca. For the determination of the dynamic modules of asphalt and asphalt mixture the methodology SHELL was followed and variables as the weighted average annual air temperature TMAP, temperature Working Mixtures - TMIX, Speed Operation of roads - VOP, the application time load - t, the frequency of application of the load - F and the rate of penetration asphalt - IP were analyzed. Results: Dynamic modules asphalt and asphalt mixture paragraph for different annual pondered average temperatures and different speeds of operation of the roads on the Department of Boyaca are presented, for asphalts type AC 60-70 and AC 80-100. Conclusion: The contribution of this research work is very useful for Design Engineers of pavement structures as it allows to know the dynamic module of a hot-dense asphalt mixture of the type INVIAS MDC-19 for rolling, taking into account the annual pondered average temperature of the project area and the operating characteristics of the road, fundamental variables for the design of lexible pavement structures.Palabras clave: Diseño de pavimentos lexibles, mecánica de pavimentos, mezclas asfálticas, módulos dinámicos


Author(s):  
Danuta Kowalska ◽  
Paweł Iwanowski ◽  
Agata Kowalewska

Immediately after completion airfield pavements begin a gradual deterioration that is attribute to several factors. One of the major elements contribute to airfield pavement deterioration is exposure to the environment (freezingthawing and de-icing salts). Air-voids microstructure in cement-based materials is an important feature related to the freeze-thaw durability of these materials since all the adverse influences are result of potentially harmful ionic fluids and aggressive gas transport through the concrete and the transport properties strongly depend on the morphology of the pores inside the concrete. For revealing the porous microstructure in airfield pavement concrete X-ray tomography method was used. New and advance methodologies have been developed to determine the basic parameters of air entrainment in concrete (total content of the air, specific surface area of the air-voids system, spacing factor and content of micropores) by summing the distances traversed across a given component along a series of regularly spaced lines in one or more planes intersecting the sample. Using the method mentioned above, to meet requirements of PN-EN 480-11 specification (describes procedure for microscopical determination of air voids characteristics in hardened concrete), the original software was applied – AVCT (Air Void by Computed Tomography) computer programme. The specimens for CT testing were cylinders extracted by drilling out from the investigated concrete core or cubic specimen. The CT method does not require any special processing of the surface of tested specimen as opposed the common method according to PN-EN 480-11, by which the properly polished section is a prerequisite for obtaining proper results of air voids characterization. The paper presents the results of the evaluation of air-voids microstructure in concrete conducted with the application of computed tomography method. Exemplary images of distribution and size of air-voids in concrete specimens have been presented. Special attention was paid to obtain effective image resolution.


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