Structural and mechanical properties of asphalt mixtures - basis for rationing of their technological properties

Research deals with granite siftings as fine aggregate possibilities to be used for manufacturing cleaved surface exterior concrete bricks. The article describes the influence of granite siftings on the technological properties of concrete mixture and on the physical mechanical properties of cleaved surface exterior concrete bricks formed using these mixtures and forecasts product durability. The following several compositions of concrete mixture for producing exterior concrete bricks are composed: using only 0/4 fraction sand (B1) as a fine aggregate, using only 0/2 fraction granite siftings (B2), and 50% of 0/4 fraction sand replacing with 0/2 fraction granite siftings (B3) depending on the volume. The products were formed in metal moulds; at a later stage, they were cleaved in half. The technological properties of concrete mixture and the physical mechanical properties of cleaved surface exterior concrete bricks formed using the above introduced mixtures were tested forecasting product durability. The results of the conducted research reveal that due to the properly selected ratio between sand and granite siftings in the fine aggregate, granite siftings may be used for manufacturing cleaved surface exterior concrete bricks.

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Effect of RAP on the mechanical properties of registered asphalt mixtures in Flanders

Life-Cycle of Engineering Systems ◽

10.1201/9781315375175-46 ◽

2016 ◽

pp. 399-405

Author(s):

J. Anthonissen ◽

W. Van Den Bergh ◽

J. Braet

Keyword(s):

Mechanical Properties ◽

Asphalt Mixtures

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The Effect of Ageing on Chemical and Mechanical Properties of Asphalt Mortar

Applied Sciences ◽

10.3390/app8112231 ◽

2018 ◽

Vol 8 (11) ◽

pp. 2231 ◽

Cited By ~ 4

Author(s):

Ruxin Jing ◽

Xueyan Liu ◽

Aikaterini Varveri ◽

Athanasios Scarpas ◽

Sandra Erkens

Keyword(s):

Mechanical Properties ◽

Asphalt Mixtures ◽

Pavement Performance ◽

Frequency Sweep ◽

Carbonyl Index ◽

Mineral Particles ◽

Tension Tests ◽

Ftir Spectrometry ◽

Diffusion Paths ◽

Asphalt Mortar

Asphalt mortar is a mixture of bitumen, filler, and sand. Mortar plays an important role in asphalt mixtures as it serves as the adhesive between the coarser aggregates. Due to the effect of bitumen ageing, the chemical and mechanical properties of asphalt mortar evolve with time. The mortar becomes more brittle and prone to cracking, thus leading to inferior pavement performance. In this study, Fourier transform infrared (FTIR) spectrometry was used to quantify changes in the chemical functional groups related to ageing and to calculate the carbonyl and sulfoxide indices. In addition, frequency sweep tests and uniaxial tension tests were performed by means of dynamic shear rheometer (DSR) tests to determine evolution of the stiffness and strength due to ageing. Two different oven ageing protocols were used to evaluate the effect of fine mineral particles on bitumen ageing. The protocols differed with respect to the order of ageing and mixing of the constituents. The results showed that both the chemical and mechanical properties of mortars significantly changed with ageing. Specifically, the carbonyl index, stiffness, and strength of the mortar increased. Under the same ageing conditions, a higher ageing level was observed for mortars produced by first mixing and then ageing compared to the mortars produced by mixing aged bitumen with filler and sand. This could be due to the presence of sand and filler particles, which resulted in an increased length of diffusion paths and consequently a slower ageing process.

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Evaluation of Short-Term Aging Protocol for Asphalt Mixtures

Applied Sciences ◽

10.3390/app9142783 ◽

2019 ◽

Vol 9 (14) ◽

pp. 2783 ◽

Cited By ~ 1

Author(s):

Sirin ◽

Paul ◽

Kassem ◽

Ohiduzzaman

Keyword(s):

Mechanical Properties ◽

Asphalt Pavement ◽

Road Construction ◽

Asphalt Mixtures ◽

Pavement Performance ◽

Design Stage ◽

Construction Site ◽

Short Term ◽

Compaction Processes

Asphalt mixtures are subjected to short-term aging during the production, placement, and compaction processes. Proper evaluation of asphalt pavement performance relies on the accurate characterization of asphalt mixtures during the design stage. In this study, three different loose asphalt mixtures often used in Qatar were evaluated to develop a laboratory short-term aging procedure. Sample mixtures 1 and 3 were collected from a construction site, while mixture 2 was obtained from an asphalt plant. Virgin aggregates and binders were also collected to reproduce the mixtures in the laboratory. Laboratory-produced mixtures were conditioned at 135 °C using various time durations. The mechanical properties of laboratory-produced mixtures were compared to those of mixtures produced on site. The results of the mechanical and binder testing demonstrated that the proper short-term aging protocol for asphalt mixtures often used in road construction in the State of Qatar would involve heating asphalt mixtures for 4 h at 135 °C before laboratory compaction.

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Impact of Preheating Temperatures and RAP Characteristics on the Activation of RAP Binder

Applied Sciences ◽

10.3390/app10238378 ◽

2020 ◽

Vol 10 (23) ◽

pp. 8378

Author(s):

Yifu Meng ◽

Liping Liu

Keyword(s):

Mechanical Properties ◽

Asphalt Pavement ◽

Asphalt Mixtures ◽

Reclaimed Asphalt Pavement ◽

Reclaimed Asphalt ◽

Central Plant ◽

Preheating Temperature

Reclaimed asphalt pavement (RAP) is preheated to 120 °C or lower in hot central plant recycling due to specification and equipment limitations. However, the insufficient activation of reclaimed asphalt (RA) caused by low preheating temperature may affect the final properties of reclaimed asphalt mixtures (RAM) and lead to insufficient utilization of RA binder. This study evaluated the influence of preheating temperature and aging of RA binder on binder activation by producing specimens with 100% RAP. The volumetric and mechanical properties of specimens were analyzed to reflect the effect of activation. The results indicate that preheating temperature has a significant impact on the activation of RA binder. Regardless of the source of RAP, RA binder can be highly activated at 180 °C, while the degree of activation decreases significantly at 120 °C. By using an artificial RAP with different degrees of aging, the aging of RA binder is found to be harmful to activation only when the preheating temperature is low (such as 120 °C). Hence, if the equipment is capable of doing so, it is better to raise the preheating temperature of RAP to improve the activation of RA binder, especially for binder with a higher degree of aging.

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