Properties of Foamed Asphalt for Warm Mix Asphalt Applications

Newcomb, D E; Arambula, Edith; Yin, Fan; Zhang, Jun; Bhasin, Amit; Li, Wei; Arega, Zelalem

doi:10.17226/22145

Cited by 57 publications

(40 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Thereby, the additional effects of asphalt foaming due to adding zeolite could be insignificant and, furthermore, the forming asphalt mastic became stiffened due to adding zeolite, which is confirmed by other researchers' studies [27]. On the other hand, the observed phenomenon could be also related to the reported findings [58] about the negative impact of higher foamed water contents on the asphalt mixture workability-the When analysing the presented compactability curves, it is possible to state that both reference mixes were characterised by similar compactability. The introduction of zeolites into the mixtures with foamed bitumen had a substantial impact on their compaction process, resulting in an increased air void content during the whole compaction process, on average by approximately 2.1 to 3.1% in the case of soaked and air-dry zeolites, respectively.…”

Section: Ac 16 Mixes' Compactability Test Resultssupporting

confidence: 88%

“…Thereby, the additional effects of asphalt foaming due to adding zeolite could be insignificant and, furthermore, the forming asphalt mastic became stiffened due to adding zeolite, which is confirmed by other researchers' studies [27]. On the other hand, the observed phenomenon could be also related to the reported findings [58] about the negative impact of higher foamed water contents on the asphalt mixture workability-the addition of zeolites has substantially increased the quantity of water delivered to the asphalt mix. The obtained volumetric and mechanical properties of the investigated asphalt mixtures are presented as bar charts that are supplemented with error bars denoting standard deviations of the respective means.…”

Section: Ac 16 Mixes' Compactability Test Resultssupporting

confidence: 88%

“…The desirability is only assigned a positive non-zero value when all of the specified boundary conditions were simultaneously met (i.e., ERm ≥ 12 and HL ≥ 10 s). The desired ERm and HL levels were based on previous experiences and literature [40,41,57,58]. The desirability function applied in this case is assigned with the following values: The results of foaming of the 35/50 asphalt with the WBE adhesion promoter additive that are presented in Figure 7a indicate a very limited impact of the adhesion promoter content on the maximum expansion, which is, therefore, mainly affected by the foaming water content (Table 11).…”

Section: Foamed Bitumen Binder Propertiesmentioning

confidence: 99%

See 2 more Smart Citations

Study of the Simultaneous Utilization of Mechanical Water Foaming and Zeolites and Their Effects on the Properties of Warm Mix Asphalt Concrete

2020

View full text Add to dashboard Cite

The paper aimed at assessing the feasibility of using natural zeolites as a mineral filler substitute for asphalt mixtures produced at around 120 °C temperatures with a water foamed binder and compacted at 100 °C. The tests utilized the AC 16 asphalt concrete mixture intended for the binder and base course with the mineral filler fraction amounting to 4% by wt. comprising limestone dust and zeolites (when added). A reference hot mix and warm mix with foamed bitumen were compared to two mixes with zeolites, with one containing 0.4% of a water-modified (20% moisture content) zeolite and the second containing 1.0% of natural air-dried zeolite. The investigations included: assessment of campactability using a gyratory compactor, air void content, indirect tensile strength before and after conditioning with one freeze-thaw cycle, and the resulting resistance to moisture and frost damage. The mixtures with zeolites exhibited decreased compactability when compared to reference mixes, which the Marshall samples confirmed. The mechanical properties have also deteriorated in zeolite-bearing mixtures, which was partially accounted to the decreased compaction level. It was concluded that the temperature of the mixture production was too low for the zeolite water to significantly improve the compactablity of the asphalt mixture and its mechanical parameters.

show abstract

Section: Ac 16 Mixes' Compactability Test Resultssupporting

confidence: 88%

“…Thereby, the additional effects of asphalt foaming due to adding zeolite could be insignificant and, furthermore, the forming asphalt mastic became stiffened due to adding zeolite, which is confirmed by other researchers' studies [27]. On the other hand, the observed phenomenon could be also related to the reported findings [58] about the negative impact of higher foamed water contents on the asphalt mixture workability-the addition of zeolites has substantially increased the quantity of water delivered to the asphalt mix. The obtained volumetric and mechanical properties of the investigated asphalt mixtures are presented as bar charts that are supplemented with error bars denoting standard deviations of the respective means.…”

Section: Ac 16 Mixes' Compactability Test Resultssupporting

confidence: 88%

Section: Foamed Bitumen Binder Propertiesmentioning

confidence: 99%

See 1 more Smart Citation

Study of the Simultaneous Utilization of Mechanical Water Foaming and Zeolites and Their Effects on the Properties of Warm Mix Asphalt Concrete

2020

View full text Add to dashboard Cite

show abstract

“…To minimise the influence of the observer on the results of the foaming parameters, i.e., on the maximum expansion (ER) and the half-life of the foam (HL), the prototype digital measuring device was used. The device is primarily based on the use of a highly accurate laser sensor, similar to that used by Newcomb et al [ 27 ], for non-contact measurement of displacement based on the principle of optical triangulation. In [ 28 ], a laser was also used as the basic tool for measuring the change in the volume of asphalt foam.…”

Section: New Testing Methods For Foam Decay Determinationmentioning

confidence: 99%

Bitumen Foaming Optimisation Process on the Basis of Rheological Properties

2018

View full text Add to dashboard Cite

This article discusses the results of bitumen foam properties optimisation with respect to three factors: air pressure, bitumen temperature and amount of water. The test materials were unmodified bitumen 50/70 and bitumen 50/70 modified with 2.5% synthetic wax. The experiment was designed according to the 3(3−1) fractional factorial design. The distribution of parameters of bitumen foam were measured with the authors’ original apparatus using a laser beam. This measurement method increased the accuracy of maximum expansion ratio (ER) and half-life (HL) estimation. Based on HL and ER results, it was found that the foaming process increased bitumen stiffness due to the dynamic ageing of the bitumen. The experimental design allows more effective control over the properties of foamed bitumen with respect to its intended use. The presence of synthetic wax extended the half-life of the bitumen foam.

show abstract

“…Similarly, Arega et al worked with a laser system to quantify unstable/short-life bubbles and semistable/long-life bubbles from Wirtgen's foaming equipment (Arega et al 2014). In addition, the most comprehensive research project to date, NCHRP Project 09-53, Newcomb et al evaluated all three foaming machines using a laser system to capture maximum expansion ration, rate of collapse of semi-stable foam, the foamability index and the SAI (Newcomb et al 2015). In addition, NCHRP 09-53 explored the intermediate-and low-temperature performance using the Dynamic Shear Rheometer and Bending Beam Rheometer.…”

Section: Introductionmentioning

confidence: 99%