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Comparison of flexural strength and crack propagation test characteristics of SMA mixtures including the ageing impact
Published in Andreas Loizos, Imad L. Al-Qadi, A. (Tom) Scarpas, Bearing Capacity of Roads, Railways and Airfields, 2017
Pavla Vacková, Jan Valentin, Petr Mondschein
Stone Mastic Asphalt (SMA) mixtures are a type of hot asphalt mixture used in surface layers of heavy-duty pavements, like motorways. SMA mixtures are characterized by discontinuous granularity and higher bitumen content compared to asphalt concrete. The mixture has coarse aggregate skeleton, which provides good stone-on-stone contact between the particles. The cohesion of the skeleton is secured by the mastic, which is formed by a mix of increased content of a Polymer Modified Bituminous binder (PMB), mineral filler and cellulose fibres.
Investigation of the usability of aggregates produced from sea shell in SMA pavements with different addition methods
Published in Road Materials and Pavement Design, 2023
On the other hand, the performance of asphalt pavement can be improved by changing the mixture type in terms of gradation. Stone mastic asphalt (SMA) is a gap-graded hot mix type with a high proportion of coarse aggregates, known for its particularly high deformation resistance. Stone mastic asphalt first appeared in order to reduce the damage to wearing courses by studded tyres. SMA is a mixture of consisted of the coarse aggregate skeleton, fine aggregate filling the voids and filler-bitumen mortar. Coarse aggregate carries traffic loads thanks to high grain contact and internal interlocking. Mortar, on the other hand, increases the durability due to its high bitumen ratio by filling the gaps. Since the bitumen ratio is high, fibre material is added to the SMA mixture in order to prevent the bitumen from draindown of the mixture. Its cost is higher due to the use of highly binder and stabilizing additives (Blazejowski, 2011; Orhan, 2012).
Erosion mechanism of sea salt solution on the performance of SBS-modified asphalt mixtures
Published in International Journal of Pavement Engineering, 2022
Rui Zhang, Naipeng Tang, Xiankun Deng, Hongzhou Zhu, Chunli Su, Yuan Xi
The styrene–butadiene-styrene (SBS)-modified asphalt from a local asphalt supplier was used in this study. SBS polymer is linear SBS polymer, and the amount was 4.5% by weight of the base asphalt binder. Conventional properties of SBS-modified asphalt met the requirements of the standard ASTM D5 (ASTM 2006a), ASTM D36 (ASTM 2006b), ASTM D113 (ASTM 2007) and ASTM D4402 (2015) and the detailed test results were shown in a previous study (Zhang et al.2022). The aggregates used in this paper were limestone and mineral powder produced in Chongqing, and their basic properties are presented in Table 1, which meet the requirements of JTG E42-2005 (JTG E42-20052005). To reduce the influence of aggregate particle size variation on the mechanical properties of asphalt mixture specimens, the aggregates were screened according to standard gradations. Stone mastic asphalt (SMA) is currently an internationally recognised asphalt mixture with good durability. SMA-13 mixtures were used in this paper, and their gradation is shown in Figure 1.
Rutting analysis of different rubberised stone mastic asphalt mixtures: from binders to mixtures
Published in Road Materials and Pavement Design, 2021
Ayad Subhy, Davide Lo Presti, Gordon Airey, Iswandaru Widyatmoko
Stone Mastic Asphalt (SMA) comprises a coarse aggregate skeleton filled with a high content of bitumen/filler mortar, and a relatively high binder content. The stone-to-stone aggregate offers excellent rutting properties while the bitumen/filler mortar offers good fatigue properties. One of the known issues associated with SMA is the risk for binder drain down during production and transportation to site. Often additives such as cellulose fibres are used to stabilise the mixture and prevent binder drain down (Ahmadinia et al., 2011; Ameli et al., 2020; Manosalvas-Paredes et al., 2016; Nejad et al., 2010; Sarang et al., 2016). Inclusion of recycled tyre rubber in bituminous materials offers some advantages in terms of enhancing the pavement performance and helping solve environmental problems that are related to hazardous landfill (Liu et al., 2012; Manosalvas-Paredes et al., 2016). Recycled tyre rubber has been successfully used in SMA and other applications such as surface dressing (chip seal) binders and SAMIs (Akisetty et al., 2009b; Khalid & Artamendi, 2004; Liu et al., 2012). The gap grading of SMA mixtures has proven to adequately accommodate the thicker film thicknesses of rubberised bitumen (Venudharan et al., 2017). The high viscous nature of rubberised bitumens can also prevent the binder drain down associated with SMA mixtures (Manosalvas-Paredes et al., 2016).