scholarly journals Effects of Cement and Emulsified Asphalt on Properties of Mastics and 100% Cold Recycled Asphalt Mixtures

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 754 ◽  
Author(s):  
Yanan Li ◽  
Yuchao Lyv ◽  
Liang Fan ◽  
Yuzhen Zhang

Cold recycled asphalt mixtures (CRAM) are a cost-effective and environmentally-friendly way to reuse reclaimed asphalt pavement (RAP). This paper evaluates the rheological properties and microstructure of mineral filler-asphalt mastic, mineral filler-residue mastic, and cement-residue mastic. Then, based on the premise of using 100% RAP with a gradation that was determined experimentally, the effects of emulsified asphalt and cement on the porosity, indirect tensile strength, tensile strength ratio, dynamic stability, and mechanical properties of CRAM were evaluated. It was found that the rheological properties and cohesive coefficient of the cement-residue mastic varied differently to those of the first two types of mastic and the results show that the addition of cement can greatly improve the interfacial bonding between binders and fillers in the mastic, thereby improving the water damage resistance and high-temperature stability of CRAM. The relationships between cement content and the dynamic modulus and phase angle of CRAM are different to that for emulsified asphalt obviously. In addition, under certain conditions, the properties of CRAM can meet the requirements of relevant technical specifications for its application to subsurface layer of pavement. Hence, the use of 100% RAP in CRAM may be feasible.

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Tao Ma ◽  
Hao Wang ◽  
Yongli Zhao ◽  
Xiaoming Huang ◽  
Yuhui Pi

This study focused on the key factors affecting the tensile strength of cold recycled asphalt mixture with cement and emulsified asphalt. The specific surface areas and strength of RAP were analyzed. The interaction between the emulsified asphalt and cement was observed. Comprehensive laboratory testing was conducted to evaluate the influences of RAP, emulsified asphalt, and cement on the tensile strength of cold recycled asphalt mixture. It is found that although RAP is used as aggregates, its inner structure and strength are much different from real aggregates. The strength of RAP has decisive effect on the strength of cold recycled asphalt mixture. New aggregates and fine gradation design can help improve the bonding between RAP and binder. For emulsified asphalt, slow setting of asphalt can give sufficient time for cement to hydrate which is helpful for strength formation in the cold recycled asphalt mixture. The high viscosity of asphalt can improve the early strength of cold recycled asphalt mixture that is important for traffic opening in the field. Cement is an efficient additive to improve the strength of cold recycled asphalt mixtures by promoting demulsification of emulsified asphalt and producing cement hydrates. However, the cement content is limited by RAP.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2779
Author(s):  
Siyue Zhu ◽  
Zirui Xu ◽  
Xiantao Qin ◽  
Menghui Liao

Cement-emulsified asphalt mixture (CEAM), a kind of cold mix asphalt mixture, has the advantages of energy conservation and emission reduction as well as easy construction. However, the performance of CEAM is not as good as hot mixed asphalt mixtures. Hence, in this study, two different fibers were adopted as the reinforcing phase to improve the comprehensive properties of CEAM. The results indicated that the addition proportion and curing time were crucial to fiber-reinforced cement-emulsified asphalt mixture (FRCEAM). The compressive strengths, water stability, and raveling resistances of FRCEAM preparations with polyester or brucite fibers (FRCEAM-PF and -BF, respectively) were enhanced significantly. FRCEAM-PF had the maximum flexural tensile strength and strain, which meant that its low-temperature performance was the best compared to FRCEAM-PF and CEAM. However, the contribution of PF to CEAM high-temperature stability was greater than that of BF. Fiber addition to CEAM not only enhanced the cycles of fatigue loading but also reduced sensitivity to changes in stress level. Furthermore, FRCEAM-BF durability was slightly better than that of FRCEAM-PF. SEM analysis indicated that fibers provided bridging and meshing effects. Although PF and BF showed different enhancement effects, both mixtures met the requirements for hot mixed asphalt mixtures.


2011 ◽  
Vol 266 ◽  
pp. 175-179 ◽  
Author(s):  
Yuan Xun Zheng ◽  
Ying Chun Cai ◽  
Ya Min Zhang

In order to discuss the effect of the basalt fiber on reinforcing pavement performance of asphalt mixtures, the optimum dosage of asphalt and fibers were studied by the method of Marshall test and rut test firstly. Then pavement performances of basalt fiber-modified asphalt mixtures were investigated through tests of high temperature stability, water stability and low temperature crack resistance, and compared with that of polyester fiber, xylogen fiber and control mixture. The testing results showed that the pavement performance of fiber-modified asphalt mixture are improved and optimized comparing with control asphalt mixture, and the performance of basalt fiber-modified asphalt mixture with best composition were excelled than those of polyester fiber and xylogen fiber.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 663 ◽  
Author(s):  
Baowen Lou ◽  
Zhuangzhuang Liu ◽  
Aimin Sha ◽  
Meng Jia ◽  
Yupeng Li

Excessive usage of non-renewable natural resources and massive construction wastes put pressure on the environment. Steel slags, the main waste material from the metal industry, are normally added in asphalt concrete to replace traditional aggregate. In addition, as a typical microwave absorber, steel slag has the potential to transfer microwave energy into heat, thus increasing the limited self-healing ability of asphalt mixture. This paper aims to investigate the microwave absorption potentials of steel slag and the effect of its addition on road performance. The magnetic parameters obtained from a microwave vector network analyzer were used to estimate the potential use of steel slag as microwave absorber to heal cracks. Meanwhile, the initial self-healing temperature was further discussed according to the frequency sweeping results. The obvious porous structure of steel slag observed using scanning electron microscopy (SEM) had important impacts on the road performance of asphalt mixtures. Steel slag presented a worse effect on low-temperature crack resistance and water stability, while high-temperature stability can be remarkably enhanced when the substitution of steel slag was 60% by volume with the particle size of 4.75–9.5 mm. Overall, the sustainability of asphalt mixtures incorporating steel slag can be promoted due to its excellent mechanical and microwave absorption properties.


2013 ◽  
Vol 734-737 ◽  
pp. 2287-2291 ◽  
Author(s):  
De Dong Guo

Fiber asphalt concrete has been more and more widely used in highway construction. For analyzing high and low temperature performance of fiber asphalt mixture, rheological properties of fiber asphalt mortar were studied through indoor test. Impact of Rheological properties of the fiber asphalt mortar on high temperature and low temperature properties of asphalt mixture was analyzed. Results showed that the larger fiber content was, the better performance of asphalt mixture's high temperature stability, fiber asphalt mortar rut factor and rutting tests results of asphalt mixture were linear correlation, reflecting the high temperature performance of asphalt mixture; With the increase of fiber content, variation of stiffness modulus, creep rate indicators and mixture low temperature performance was consistent, and rheological properties of fiber asphalt mortar could characterize low temperature performance of asphalt mixture.


2013 ◽  
Vol 361-363 ◽  
pp. 1655-1658
Author(s):  
Xiao Li Li ◽  
Qing Zhou Wang ◽  
Shu Yan Liu

Because of the heating limitation of old pavement and the restriction of climate, the quality of hot in-place recycled pavement was different to control. The warm m,ix asphalt technology was introduced to improve the heterogeneity and compactness of the hot in-place recycled pavement and decrease its construction temperature. The compaction characteristics of warm in-place recycled asphalt mixture were analyzed and its molding temperature was determined through the Marshall test. The pavement performance of warm in-place recycled asphalt mixture was analyzed whose results indicated that the introduction of warm mix asphalt technology was able to improve the compactness, the high temperature stability and water stability of hot in-place recycled asphalt mixture and reduce the influence of environment over its construction quality. A warm in-place recycled engineering of Shian expressway was introduced to verify the feasibility of warm in-place recycling technology which demonstrated that the warm in-place recycling technology was able to improve the heterogeneity and compaction quality of the recycled pavement and weaken the environmental pollution.


2012 ◽  
Vol 238 ◽  
pp. 22-25 ◽  
Author(s):  
Yuan Zhao Chen ◽  
Zhen Xia Li

In order to discuss the effectiveness of basalt fiber in reinforcing pavement performance of asphalt mixtures, the pavement performances of basalt fiber asphalt mixtures were investigated by tests of high temperature stability, water stability and low temperature crack resistance, and compared with the pavement performance of asphalt mixtures with polyester fiber and xylogen fiber, and that of reference mixture. The results show that pavement performance of fiber asphalt mixture are improved and optimized comparing with reference asphalt mixture, the performance of asphalt mixture with basalt fiber are excelled than those with polyester fiber and xylogen fiber while the dosage of fibers is keeping at the optimum.


Alloy Digest ◽  
2007 ◽  
Vol 56 (6) ◽  

Abstract Timetal 6-2-4-2 has a combination of tensile strength, creep strength, toughness, and high-temperature stability for long-term application at temperatures up to 538 deg C (1000 deg F). This datasheet provides information on composition, physical properties, microstructure, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, and joining. Filing Code: TI-140. Producer or source: Timet.


2012 ◽  
Vol 204-208 ◽  
pp. 4143-4146
Author(s):  
Zhong Guo He ◽  
Xin De Tang ◽  
Wen Jun Yin ◽  
Yi Fan Sun ◽  
Zhong Bo Liu

Montmorillonite/SBS composite modifed asphalts were prepared by mixing montmorillonite with SBS-modified asphalt, further the corresponding asphalt mixtures were obtained. The paving technical indexes of the mixture such as physical properties, moisture suscepyibility, and high temperature stability were tested, and compared with that of the corresponding SBS-modifed asphalt mixture and base asphalt mixture. The results demonstrate that the montmorillonite/SBS composite modifed asphalt mixture exhibites enhanced stability, improved flow value and moisture susceptibility, and increased high temperature stability.


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