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Sustainable pavement recycling: Utilization of cement and asphalt waste dust to improve CBR and permeability
(2025-09-01)
Chaiyaput, Salisa
;
Thatmas, Natthapong
;
Nguyen, Trong Nghia
;
Huan, Vo Nguyen Phu
;
Mase, Lindung Zalbuin
This study aims to utilize asphalt waste dust, a pollutant by-product of the asphalt production process, to improve the quality of recycled pavement materials for use as base course materials, under the standards of the Department of Rural Roads and the Department of Highways, Thailand. The mixture consisted of 70 % by weight (wt%) reclaimed asphalt pavement (RAP), 30 wt% crushed rock (CR), 3.5 wt% cement (C), and 20 wt% asphalt waste dust (AD), in comparison to the general pavement recycling (RAP-CR-C). Compaction test, permeability test, California Bearing Ratio (CBR) test, and scanning electron microscope (SEM) analysis were performed under all testing conditions. The highest performance was achieved for the recycled pavement materials, containing 3.5 wt% cement and 20 wt% asphalt waste dust (RAP-CR-C-AD20). The coefficient of permeability was 2.32 × 10-7 cm/s under pressurized constant head, 2.40 × 10-7 cm/s under an 8 mm falling head, and 2.59 × 10-7 cm/s under a 14 mm falling head. The CBR values were 493 % at 0.1 in (2.54 mm) penetration and 491 % at 0.2 in (5.08 mm) penetration. The RAP-CR-C-AD20 exhibited a low coefficient of permeability but a high CBR, compared to those of RAP-CR-C, and above the minimum base course requirement (CBR > 80 %). This study highlights the potential of using asphalt waste dust in pavement recycling as an innovative solution that not only reduces waste but also contributes to sustainable road construction practices.
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PERMEABILITY OF THE DIKE 1’S MATERIALS OF KAENG KRACHAN DAM, THAILAND
(2022-02-01)
Sirikaew, Uba
;
Hopeancharoen, Witthawin
;
Seeboonruang, Uma
Dike 1 of Kaeng Krachan Dam located in Phetchaburi province of Thailand constructed in 1966 with a reservoir capacity of 710 million m3. This large-scale project provides more than 55 years of irrigation and flood protection. Risk evaluation of dam is needed to be performed. The calibration of engineering properties of the Dike 1 is conducted because there is no database of those properties. The existing Dike 1 cross-section is a soil model, used for calculation. Piezometric level and flow rate obtained from the dam instruments were calibrated with the hydraulic head and the flow rate was determined by the SEEP/W model. The permeability coefficient of the Dike 1 materials can be analyzed by the calibration technique. The data of the dam instruments are helpful information, and the computer program is friendly to use. The coefficient of permeability of the soil of the Dike 1 of Kaeng Krachan Dam is determined and applied to risk analysis.
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Permeability and setting time of bio-mediated soil under various medium concentrations
(2021-04-01)
Treebupachatsakul, Treesukon
;
Kamchoom, Viroon
The bio-clogging using bacteria can be an eco-friendly and sustainable alternative to conventional grouting methods for seepage control. However, it remains unclear to date how the dilute concentration of bacterium and medium during field installation can affect the setting time of bacterium and its correlation with permeability reduction. In this study, the setting time of bacterium and its effectiveness in permeability reduction were addressed through experimental and theoretical investigations. A series of sand column was cultivated using different concentrations of Leuconostoc mesenteroides and culture medium. The distribution and composition of the bacterial product (i.e. dextran) were observed by refractometer, scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS). Soil permeability was recorded using a constant head test. The results revealed that bacterium was effective to produce dextran at the setting time of about 5 d after installation. This dextran can reduce the permeability of bio-mediated soil by two orders of magnitude, even without culture medium supply. In general, the dextran production decreased proportionally with increase of bacterium and medium concentration. However, at 50% bacterium and medium concentration by weight, it still has a significant influence on permeability reduction with similar setting time, compared to 100% concentration.
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Permeability of fluid flow through a periodic array of cylinders
(2015-01-01)
Chamsri, Kannanut
;
Bennethum, Lynn S.
The three-dimensional model of an incompressible Newtonian viscous fluid slowly flowing through a periodic array of cylinders is considered. We use homogenization to determine a system of equations that are then solved numerically to calculate the permeability. We determine the permeability as a function of the angle the cylinders make with the bottom surface. Numerical results are obtained using a Taylor-Hood mixed finite element method. The numerical approach is validated by comparing the results with computed results of Rocha and Cruz, for a simple cubic array of spheres, with good agreement. Results are presented for different cylindrical densities and angles. When the flow aligns and is perpendicular to an array of cylinders, the results are validated with experimental data. The spherical part of the permeability is compared with the Kozeny-Carman equation. Applications of these results include modeling fluid flow through biological hairlike structures such as animal hair, glass rods, fiberglass, filter pads, polymer gel, collagen, nylon fibers and natural rice field or trees.

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