scholarly journals Laboratory Trials Of Cold Recycled Foamed Bitumen Asphalt: Raf Waddington

Author(s):  
Helena Isabel Lacalle Jiménez ◽  
Jessica Tuck

Abstract The Defence Infrastructure Organisation requested a pavement evaluation on RAF Waddington and the results indicated that runway rehabilitation and reprofiling was needed in order to meet the physical design requirements set out in the Manual of Aerodrome Design & Safeguarding. The presence of tar in a layer of the old pavement promoted the option of cold recycling this material into the new structure. This paper presents the results from a laboratory investigation into the suitability of cold recycled foamed bitumen asphalt to be used in the structural layers of an airfield pavement. Laboratory mixture designs with foamed bitumen, incorporating asphalt planings from RAF Waddington runway, were produced in URS Infrastructure and Environment Ltd. laboratory. Specimens were used to assess mix performance and in order to add confidence to the design. The last objective of the research was to demonstrate that asphalt planings from RAF Waddington could be recycled into foamed asphalt for incorporation in the runway rehabilitation works. The optimum binder content was determined from Indirect Tensile Stiffness Modulus tests and Indirect Tensile Strength tests, concluding that the optimum binder content was 3.3% by mass. As a common practice in the UK, up to 1.5% by mass of cement was added to the mixture to improve early life performance. To assess the foamed bitumen samples’ performance with time, specimens were prepared and cured for 28, 180 and 360 days at different temperatures. Post curing, the specimens were tested for a range of performance criteria including fatigue, stiffness and durability. The study found that asphalt sampled from the runway at RAF Waddington can be recycled into foamed asphalt, meeting the requirements of Defence Infrastructure Organisation Specification 050.

2016 ◽  
Vol 11 (4) ◽  
pp. 291-301 ◽  
Author(s):  
Marek Iwański ◽  
Anna Chomicz-Kowalska

This paper presents findings of a study concerning the influence of binder type on the mechanical properties of road base in the cold recycling technology. The principal aim of this investigation was to evaluate the mixes in scope of susceptibility to moisture and low-temperatures. In the comparative research foamed bitumen and bitumen emulsion were used in four different concentrations (2.0%, 2.5%, 3.0%, 3.5%). The materials used in the study were reclaimed from an existing road construction layers: reclaimed aggregate from the road base and reclaimed asphalt pavement obtained by milling the surface and binder course. Portland cement in 2.0% concentration was used as a hydraulic binder. The evaluated parameters were: indirect tensile strengths, tensile strength retained and indirect tensile stiffness modulus at 25 °C. These tests were complemented by an evaluation of susceptibility to moisture and frost according to modified procedures implemented by American researchers: Tunnicliff, Root and Lottman. Moreover, tests for low-temperature cracking were conducted according to Finnish standard. The investigations showed that the use of foamed bitumen for road base layer produced in the cold recycling technology results in better mechanical properties and resistance to moisture and frost compared to using bitumen emulsion. The use of 2.5% of foamed bitumen and 2.0% of Portland cement in the recycled road base allowed to meet the established criteria.


Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5473
Author(s):  
Katarzyna Konieczna ◽  
Piotr Pokorski ◽  
Wojciech Sorociak ◽  
Piotr Radziszewski ◽  
Dawid Żymełka ◽  
...  

The benefits of the use of cold recycling mixtures (CRMs) in pavement rehabilitation are associated with both the reduction of natural resource consumption by replacing them with recycled materials and the reduction of energy consumption during their production and paving. The evolution of the stiffness of CRMs in road construction and the fatigue life of pavements with CRM base layers are still being investigated. In this paper, CRMs with 1% cement content, called bitumen-stabilized materials with bitumen emulsion (BSM-Es), were examined. Mixtures that were differentiated in terms of Reclaimed Asphalt Pavement (RAP) content, as well as the amount and type of bitumen emulsions, were subjected to indirect tensile stiffness modulus (ITSM) tests at 5 °C, 13 °C, and 20 °C. The thermal sensitivities of the BSM-E mixtures were analyzed. BSM-E mixture stiffness modulus levels at various temperatures were determined using a statistical approach. On the basis of the results obtained, a discussion on the mechanistic-empirical design of flexible pavements with BSM-E base layers is presented. The potential benefits of using BSM-E materials in road construction in certain aspects of pavement life are indicated.


2019 ◽  
Vol 27 (2) ◽  
pp. 16-20
Author(s):  
Jakub Šedina ◽  
Jan Valentin ◽  
Petr Mondschein ◽  
Jan Suda

AbstractIn addition to bituminous binders (bituminous emulsion, foamed bitumen), hydraulic binders are applied in cold recycling technologies to increase the strength of a final structural layer as well as to increase its resistance to water and frost impacts. This paper deals with the use of energy by-products from fluidized bed coal combustion and mineral waste and their modification into reactive material with the potential of replacing commonly used hydraulic binders. The increase in the reactive potential takes place through a high-speed milling process where the mechanical-chemical activation of the material takes place. This process is associated with the refinement of the material, a higher proportion of micro and nanoparticles, an increased surface area, opening of particles, etc. The material treated exhibits binding properties, and it can be used as an active filler that allows for the partial or complete substitution of hydraulic binders. The experimental part is focused on the application of alternative binders to cold recycling mixtures and their assessment according to valid technical regulations, i.e., an assessment of their indirect tensile strength and water susceptibility as well as compressive strength and resistance to the effects of water and frost.


2017 ◽  
Vol 7 (080) ◽  
pp. 127 ◽  
Author(s):  
H. I. Lacalle-Jiménez ◽  
J. P. Edwards ◽  
N. H. Thom

Cold recycled bound materials (CRBMs) provide an economic and environmental advantage for pavements since they decrease energy and raw material consumption. However, design methods for airfield pavements do not include key CRBM properties. In this paper an empirical-mechanistic method is used to study airfield pavement design with CRBM in order to develop design guidance. The aim of the paper is to obtain the inputs related to material properties needed for use in this method. For this purpose, CRBM containing reclaimed asphalt, with fly ash, cement and foamed bitumen as stabilising agents, was characterised. The methodology included indirect tensile stiffness modulus (ITSM) and indirect tensile fatigue tests (ITFT) in strain control mode. The inputs needed for a pavement design analysis with CRBM were then obtained. The results showed the importance of further study on CRBM fatigue to understand the behaviour of these mixes under cyclic loading.


Author(s):  
Ahmed Saidi ◽  
Ayman Ali ◽  
Wade Lein ◽  
Yusuf Mehta

The objective of this paper is to present a procedure for designing cold in-place recycling (CIR) mixtures through balancing rutting and cracking for these mixtures. Four CIR mixtures were prepared using two recycling agents (foamed and emulsified asphalts), and compacted at two gyration levels (30 and 70 gyrations). The CIR mixtures were prepared at a constant water content of 3% and a constant cement content of 1% while curing of the compacted samples was conducted by placing them in an oven for three days at 140°F (dry curing). The CoreLok device was used for measuring air voids in compacted samples. The rutting susceptibility of these mixtures was then evaluated using the asphalt pavement analyzer (APA) and dynamic complex modulus (|E*|) while resistance to cracking was assessed using the indirect tensile strength (ITS) test and fracture energy as determined using the semi-circular bend (SCB-FE) test. A demonstration of how these tests were utilized to select a performance balanced optimum binder content for each of the four CIR mixes was also presented. The developed balanced mix design approach was used successfully for designing four CIR mixtures and selecting the optimum binder content for each mix. The results also showed that using a higher compaction level leads to increasing both foamed and emulsified asphalt CIR mixtures’ ability to resist rutting. In terms of cracking, SCB-FE results showed that foamed asphalt mixtures were better at resisting cracking than emulsified asphalt CIR mixtures.


2020 ◽  
Vol 841 ◽  
pp. 108-113
Author(s):  
Marcos Ariel Villanueva Guzmán ◽  
Horacio Delgado Alamilla ◽  
Elia Mercedes Alonso Guzmán ◽  
Wilfrido Martínez Molina ◽  
Hugo Luis Chávez García ◽  
...  

Foamed bitumen improves the properties of base layer, increasing the number of equivalent axles allowed, as result of this is a durable pavement. To achieve this, base layer’s design must count with an amount of filler, to increase the stony aggregate fraction. This research consists with two different types of filler, lime and cement, 1% in dosage respect to the stony aggregate weight. Has been discovered now, that the RAP (reclaimed asphalt pavement) aggregate in addition to mitigate environmental problems, has a significant impact value on the mechanic resistance of the mix.


2016 ◽  
Vol 64 (4) ◽  
pp. 763-773 ◽  
Author(s):  
M. Iwański ◽  
P. Buczyński ◽  
G. Mazurek

Abstract Mineral fines are a waste product of aggregate production in quarries and asphalt mixing plants. The incorporation of mineral gabbro dust into foam bitumen causes developing of a mesh reinforcement in the recycled base mixture. This mesh reinforcement, observed in a recycled base structure, induces an increase in stiffness modulus, where its elastic part of complex modulus dominates over the imaginary part. Therefore, it is possible to create a recycled mixture with a lower susceptibility to loading time/temperature. In result, the presence of gabbro dust in recycled mixture limits the magnitude of strains induced by the traffic load. This paper presents the results of the tests carried out on the mineral dusts derived from gabbro rock. Structural and functional properties of the fines were determined to prepare their characteristics. Then, the cold recycled mixtures for the road base were designed with the 5–20% mineral fines content. The mixtures were prepared in cold recycling technology with foamed bitumen. Further tests involved determining mechanical and physical properties of the recycled mixes, including air voids content, Marshall stability, Marshall quotient (stiffness), indirect tensile strength and stiffness modulus at 20°C). The results indicated a positive influence of the gabbro dusts on the investigated parameters. With the use of ANOVA tests, the significance of the influence of the gabbro dust and foamed bitumen on these properties was evaluated. Harrington’s multicriteria method was employed to establish gabbro dust and foamed bitumen amounts, the addition of which would guarantee optimal properties of the recycled base mixture.


2013 ◽  
Vol 423-426 ◽  
pp. 997-1000
Author(s):  
Ali Mohamed Abudullahi ◽  
Kwong Yiing Ting ◽  
Wee Kang Choong ◽  
Boon Hoe Goh

This study aimed to investigate the effect of temperature on stiffness modulus of asphaltic concrete. The asphaltic concrete mixture were prepared based on Marshall Mix Design method using two different types of bitumen, the 80/100 penetration grade bitumen (80/100 PGB) and Styrene-Butadiene-Styrene (SBS), both with five percent bitumen content. Indirect Tensile Stiffness Modulus (ITSM) test of 1000 N loading was then performed at three different temperatures (25 °C, 30 °C and 40 °C). The results showed that stiffness modulus decreases with increases in temperature for both 80/100 PGB and SBS, which shows the important role of temperature to stiffness modulus of asphaltic concrete. Also, the results showed a higher stiffness modulus for SBS mixtures compare to that of 80/100 PGB mixtures.


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