applied sciences Article
Pavement Performance Investigation of Nano-TiO2/CaCO3 and Basalt Fiber Composite Modified Asphalt Mixture under Freeze-Thaw Cycles Yafeng Gong, Haipeng Bi, Zhenhong Tian and Guojin Tan * College of Transportation, Jilin University, Changchun 130022, China;
[email protected] (Y.G.);
[email protected] (H.B.);
[email protected] (Z.T.) * Correspondence:
[email protected]; Tel.: +86-155-2688-5763 Received: 12 November 2018; Accepted: 7 December 2018; Published: 12 December 2018
Abstract: The objective of this research is to evaluate the pavement performance degradation of nano-TiO2 /CaCO3 and basalt fiber composite modified asphalt mixtures under freeze-thaw cycles. The freeze-thaw resistance of composite modified asphalt mixture was studied by measuring the mesoscopic void volume, stability, indirect tensile stiffness modulus, splitting strength, uniaxial compression static, and dynamic creep rate. The equal-pitch gray prediction model GM (1, 3) was also established to predict the pavement performance of the asphalt mixture. It was concluded that the high- and low-temperature performance and water stability of nano-TiO2 /CaCO3 and basalt fiber composite modified asphalt mixture were better than those of an ordinary asphalt mixture before and after freeze-thaw cycles. The test results of uniaxial compressive static and dynamic creep after freeze-thaw cycles showed that the high-temperature stability of the nano-TiO2 /CaCO3 and basalt fiber composite modified asphalt mixture after freeze-thaw was obviously improved compared with an ordinary asphalt mixture. Keywords: nanometer materials; basalt fiber; composite modified asphalt mixture; freeze-thaw cycle; damage model
1. Introduction Due to the good performance and riding quality, along with easy maintenance and repair, asphalt pavement has increased year by year in China [1]. However, the temperature sensitivity of asphalt materials is high and the mechanical properties of asphalt pavement will degrade under large temperature difference [2]. Northeast China belongs to the seasonal frozen region and the average temperature in winter can reach −20 ◦ C and above 20 ◦ C in summer. In order to improve the performance of asphalt pavement, reduce the damage of pavement, and extend the service life of pavement, nanomodification and fiber modification technologies have been applied in asphalt mixture. Nanotechnology is a new technology that has gradually emerged in recent years. Nanomaterials have been gradually applied as asphalt mixture modifiers due to their special properties not found in macroscopic materials. Ameri et al. evaluated moisture susceptibility of hot mix asphalt (HMA) with and without Zycosoil as a nano-organosilane anti-stripping additive and hydrated lime in the form of slurry. The results found that use of Zycosoil additive will increase adhesion bond between the aggregates and asphalt binders, and in turn influences the moisture resistance of the mixture to moisture damage [3]. Hamedi studied the effects of using nano-CaCO3 as an antistrip additive on moisture susceptibility of asphalt mixtures have been assessed using the surface free energy (SFE) method and modified Lottman test. Adding nanomaterials lead to the decrease of the acid component of SFE and increase of basic component of SFE for the asphalt binder that lead to an increase of Appl. Sci. 2018, 8, 2581; doi:10.3390/app8122581
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adhesion between the asphalt binder and sensitive aggregate against moisture damage [4]. Nano-TiO2 is a commonly used nanomodified material. Shafabakhsh et al. found that nano-TiO2 could effectively improve the viscosity, anti-rutting, and anti-fatigue properties of asphalt mixture [5]. Sadeghnejad et al. used nanomaterials to modify SMA and the test results showed that nano-TiO2 could improve the anti-rutting ability and splitting strength ratio and prolong the service life of an asphalt mixture [6]. Nazari et al. evaluated the microstructure and chemical properties of nanocomposite modified asphalt by X-ray and scanning electron microscopy. It was found that the addition of nanomaterials improved the fatigue resistance of asphalt mixture [7]. There are many kinds of fiber modifiers used in asphalt mixtures in recent years, such as polyester fiber, lignin fiber, carbon fiber, glass fiber, basalt fiber, etc. Different fiber modifiers have their own advantages and disadvantages. The low-temperature crack resistance of asphalt mixture is the main problem in the frozen region of northeast China. Compared with other fibers, basalt fiber is a mineral fiber that is abundant and easy to obtain in northeast China. Also, it will not cause environmental pollution. Basalt fiber has some advantages in terms of modifying road performance of asphalt mixtures. Zheng studied the pavement performances of basalt fiber, lignin fiber, and polyester fiber modified asphalt mixtures and found that the performance of the basalt fiber modified asphalt mixture was superior to that of the others [8,9]. Morova et al. studied the usability of basalt fibers in order to bear the stresses occurring at the surface layer of pavement and the optimum value of the fiber ratio leading to the optimum stability value was determined [10]. Chen found that basalt fiber, at the optimal fiber content, could improve the water stability and high-temperature stability of the asphalt mixture more effectively than lignin fiber and polyester fiber [11]. Qin studied the asphalt adsorption property, shear performance, crack resistance, and high-temperature rheological properties of asphalt modified by basalt fiber, lignin fiber, and polyester fiber. The microstructure and strengthening mechanism of basalt fiber was also studied by scanning electron microscopy. The results showed the basalt fiber can obviously improve the crack resistance of asphalt mastic than other fibers [12]. Gao et al. found that basalt fiber could significantly improve the tensile strength of asphalt mixture [13]. Chang et al. studied the low-temperature performance of asphalt mixture under salt freeze-thaw cycles with low-temperature bending experiments. The results showed that the concentration of the salt solution and freeze-thaw temperature had significant influence on the low-temperature performance of mixture. Basalt fiber improved the low-temperature performance of mixture under salt freeze-thaw cycles [14]. Davar et al. evaluated the fatigue life of basalt fiber and diatomite composite modified asphalt with four-point bending beam experiment, and the experimental results showed that basalt fiber improved the low-temperature performance of asphalt mixture [15]. Zheng et al. studied the performance of basalt modified asphalt mixture under the coupling effect of chloride erosion and freeze-thaw cycles. It was found that basalt fiber greatly improved the low-temperature bending and fatigue performances of asphalt mixture [16]. In addition, basalt fiber could improve the resistance and pavement performance of asphalt road under complex environment. Zhang et al. studied the performance improvement of asphalt mixtures modified with different modifiers at different salt concentrations and different environments. The test results showed that basalt fiber had the best improvement on mechanical properties of asphalt mixtures under salty and humid environment [17,18]. Celauro et al. studied the performances of basalt fiber modified asphalt mixture as the surface layer of bus lane pavement, and found that basalt fiber modified asphalt had good performance in resisting permanent deformation and increasing road friction [19]. The raw material cost of basalt fiber modified asphalt pavement has increased by 15–20%, but the service life of the pavement can increase by 30–40% [20,21]. From what has been discussed above, basalt fiber is suitable to be used as a modified material for asphalt pavement in northeast China. The asphalt concrete pavement in northeast China faces the freeze–thaw cycles conditions. The freeze-thaw cycles had a great threat to the durability of asphalt pavement. Many researchers analyzed the mechanism of freeze-thaw damage of asphalt mixture, in general, the water permeated and remained in the pores of the pavement, when the external temperature decreased, the pore water
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froze and volume expanded, which resulted in the generation of frost heave. When the temperature increased, ice melted into water and began the next freeze-thaw cycle. With repeated freeze-thaw cycle, the internal pore morphology and bituminous viscosity of the mixture were significantly changed and the performances of the mixture were significantly reduced [22–25]. In order to more vividly reflect the mechanism of freeze-thaw damage of asphalt mixture, research focused on the performance changes of asphalt mixture under freeze-thaw cycles through macroscopic test or mesoscopic analysis. Xu et al. studied the micro-thermodynamic behavior of asphalt mixtures under a freeze-thaw cycle with information entropy theory, X-ray tomography and image processing technology [26]. Nian performed the freeze-thaw aging test and carried out Fourier transform infrared spectroscopy quantitative to analyze the compositions and rheological properties of asphalt mixture in cold regions [27]. Xu et al. studied the internal evolution and analyzed the pore distribution changes and permeability of asphalt mixture during a freeze-thaw cycle with X-ray tomography [28,29]. Wang et al. analyzed the pore structure of semi-rigid base materials under freeze-thaw cycles with X-ray tomography [30]. Ma et al. established the performance decay model of asphalt pavement in cold regions. The results showed that the freeze-thaw cycles had a significant impact on pavement reliability. The more unstable the conditions of the freeze-thaw cycle, the greater the impact on pavement capacity [31]. Sol-Sánchez analyzed the evolution of the strength and bearing capacity of asphalt mixtures exposed to long-term moisture over several freeze-thaw cycles and a varying number of days of thermal aging. It found that the air void content has a significant influence on the long-term evolution of the mixture properties under moisture, which is a reversible process, unlike the other two climate agents studied [32]. Badeli et al. studied the changes of complex modulus of asphalt mixtures under rapid freeze-thaw cycles with different compaction and dry humidity in cold regions. They established rheological model to predict the service life and fatigue crack of asphalt mixture under freeze-thaw cycles. It was found that the freeze-thaw cycles had a more significant effect on the stiffness of the mixture [33–35]. Gong et al. studied the effect of freeze-thaw cycles on mortar with the rheological test of curved beam [36]. Linares used three representation functions to determine relaxation moduli of asphalt mixtures subject to the action of freeze-thaw cycles. It concludes that Prony series function appeared to have better prediction than other two functions in fitting raw creep compliance data of asphalt mixtures at 0, 100, 200, 250, and 300 freeze-thaw cycles as well as showing promising results in predicting the relaxation modulus of asphalt mixtures subjected to freeze-thaw cycles [37]. Lachance-Tremblay et al. used the 2S2P1D rheological model to simulate the material behavior and evaluate the evolution of linear viscoelastic properties. Repeated freeze-thaw damaged the sample and glass asphalt mixture was damaged faster than the reference mixture. However, both mixtures reached equivalent damage after 10 freeze-thaw cycles [38]. In order to improve the freeze-thaw resistance asphalt pavement, the addition of modified materials was the main methods in existing researches. Huang et al. studied the moisture resistance of asphalt mixture modified with slaked lime under freeze-thaw cycles [39]. Wei et al. studied the influence of diatomite and styrene-butadience-styrence (SBS) on the freeze-thaw resistance of waste rubber modified asphalt mixture. They established the mathematical model and accurately predicted the porosity and indirect tensile strength during freeze-thaw cycles [40]. Modarres et al. studied the effect of Cement kiln dust (CKD) as a filler material on the low-temperature characteristics of hot mix asphalt (HMA). According to the obtained results, mixes containing CKD filler demonstrated better resistance against freeze-thaw cycles compared to the control mixture containing limestone (LS). Moreover, mixes containing CKD exhibited a higher fatigue life compared to the control mix and for all mixes the fatigue life decreased by decreasing the temperature [41]. Yan et al. studied the effects of freeze-thaw cycles on the Marshall stability, flow value, and split tensile strength of stone mastic asphalt (SMA) mixtures with different lime content [42]. Xu et al. studied the effect of freeze-thaw cycles on split tensile strength and porosity of rubber modified asphalt mixture [43]. Teguedi et al. analyzed the local volume change of asphalt mixture with different reclaimed asphalt pavement (RAP) contents under freeze-thaw cycles with grid method and digital image processing technology [44].
In this paper, in order to evaluate whether the freeze‒thaw performance of nano-TiO2/CaCO3 and basalt fiber composite modified asphalt mixture meets the climate requirements of seasonal frozen area, various physical and mechanical properties under freeze‒thaw cycles were studied. Two kinds of asphalt mixtures, matrix asphalt mixture (AM) and nano-TiO2/CaCO3 and basalt fiber Appl. Sci. 2018, 8, 2581 4 of 19 composite modified asphalt mixture (NBAM), were prepared with the best oil‒stone ratio. The freeze‒thaw cycles test was carried out. The degradation and damage mechanism of physical and this paper, in order to evaluate whether the freeze-thaw performance of nano-TiO2 /CaCO3 mechanical In properties for different asphalt mixtures were analyzed. The improvements on and basalt fiber composite modified asphalt mixture meets the climate requirements of seasonal frozen mechanical properties of nano-TiO2/CaCO3 and basalt fiber composite modified asphalt mixture after area, various physical and mechanical properties under freeze-thaw cycles were studied. Two kinds freeze‒thaw cyclemixtures, were studied. of asphalt matrix asphalt mixture (AM) and nano-TiO2 /CaCO3 and basalt fiber composite modified asphalt mixture (NBAM), were prepared with the best oil-stone ratio. The freeze-thaw cyclesand testMethods was carried out. The degradation and damage mechanism of physical and mechanical 2. Materials properties for different asphalt mixtures were analyzed. The improvements on mechanical properties of nano-TiO2 /CaCO3 and basalt fiber composite modified asphalt mixture after freeze-thaw cycle 2.1. Materials were studied.
In this paper, base bitumen AH-90 was used as the binder. According to the Chinese national 2. Materials and Methods standard (JTGE40-2004) [45], AH-90 is bitumen with penetration between 80 and 100. The penetration, softening point, ductility, Brookfield viscosity and density of bitumen were determined 2.1. Materials according toIn the Standard Test Methods Bitumen and According Bituminous Mixtures for Highway this paper, base bitumen AH-90 wasofused as the binder. to the Chinese national Engineering (JTG E20-2011) [46]. The physical of the base bitumen are listed in Table 1. standard (JTGE40-2004) [45], AH-90 is bitumenindexes with penetration between 80 and 100. The penetration, softening point, ductility, Brookfield viscosity and density of bitumen were determined according to the Standard Test Methods of Bitumen Bituminous Mixtures for Highway Engineering Table 1. Basic and properties of bitumen. (JTG E20-2011) [46]. The physical indexes of the base bitumen are listed in Table 1.
Property Test Results Standard Requirements Table 1. Basic properties of bitumen. Penetration (25 °C, 5 s, 0.1 mm) 85.8 80–100 Property Test Results Standard Requirements Softening point TR&B (°C) 46.9 ≥45 ◦ C, 5 s, 0.1 mm) Penetration (25 85.8 80–100 Ductility (25 °C, cm) >150 ≥100 Softening point TR&B (◦ C) 46.9 ≥45 Brookfield viscosity (135 °C, Pa·s) 306.9 — Ductility (25 ◦ C, cm) >150 ≥100 ◦ 3 Brookfield viscosity (135 )C, Pa·s) 306.9 — — Density (15 °C, g/cm 1.016 Density (15 ◦ C, g/cm3 )
1.016
—
The basalt fiber was used in this paper to modified asphalt mixture. The appearance is shown in basalt fiber was used in this paper to modified asphalt mixture. The appearance is shown in Figure 1. TheThe basic technical properties are listed in Table 2. From previous study of our research Figure 1. The basic technical properties are listed in Table 2. From previous study of our research group group ononbasalt fiber modified asphalt mixture [47], the basalt fiber also has the low hydrophilicity, basalt fiber modified asphalt mixture [47], the basalt fiber also has the low hydrophilicity, high heat high heatresistance resistance and oil high oil absorption (oil rate absorption is fiber 6.154%). Basalt fiber provides a and high absorption (oil absorption is 6.154%).rate Basalt provides a feasibility for thefor application of composite modified asphalt. feasibility the application of composite modified asphalt.
Figure Appearance of fiber. Figure 1. 1. Appearance ofbasalt basalt fiber.
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Table 2. Technical properties of basalt fiber. Appl. Sci. 2018, 8, 2581
5 of 19 Property Test Results Standard Requirements [48] Diameter (μm) 10–13 — Table 2. Technical properties of basalt fiber. Length (mm) 6 — Moisture content ≤0.2 [48] Property(%) Test 0.030 Results Standard Requirements Combustible content 0.56 — Diameter (µm)(%) 10–13 — Length (mm) 6 — Linear density (Tex) 2398 2400 ± 120 Moisture content (%) 0.030 ≤0.2 FractureCombustible strength content (N/Tex) 0.55 (%) 0.56 — ≥0.40 Linear density (Tex) 2398 2400 ± 120 Tensile strength (MPa) 2320 ≥2000 Fracture strength (N/Tex) 0.55 ≥0.40 Tensile modulus ofstrength elasticity 86.3 Tensile (MPa)(GPa) 2320 ≥2000 ≥85 Tensile modulus of elasticity (GPa) 86.3 ≥85 ≥2.5 Elongation at break (%) 2.84
Elongation at break (%)
≥2.5
2.84
Nano-materials are white color, made by chemical methods and inorganic synthetic materials. Nano-materials are white color, made by chemical methods and inorganic synthetic materials. The molecular formula is TiO /CaCO 3, and the appearance is shown in Figure 2. It is soluble in water. The molecular formula is2TiO 2 /CaCO3 , and the appearance is shown in Figure 2. It is soluble in water. The supporting particles are rod-shaped and titanium dioxide particles are flake-shaped The supporting particles are rod-shaped andthe the outer outer titanium dioxide particles are flake-shaped 50–60 with nm), with regular structureand and excellent power. (diameter(diameter is 50–60is nm), regular structure excellentcovering covering power.
(a)
(b)
2. Images of nano (b) (b) SEMSEM images (5000×(5000×). ). 2 /CaCO 3 materials: (a) Figure Figure 2. Images of nano TiOTiO 2/CaCO 3 materials: (a)appearance; appearance; images
The coarse and fine aggregates used in the test were sieved, and the physical properties of coarse
The aggregates, coarse andfine fine aggregates inpowders the test were weretested sieved, and the properties aggregates and used mineral according to physical the requirements of JTGof coarse aggregates, fine aggregates and E42-2005 [49]. The results aremineral shown inpowders Tables 3–5.were tested according to the requirements of JTG E42-2005 [49]. The results are shown in Tables 3, 4, and 5. Table 3. Physical properties of aggregate.
Granular Grade (mm)
Granular Grade (mm) 13.2 9.5 4.75 2.36 1.18 0.6 0.3 0.15 0.075
Apparent Table 3. Specific Gravity
13.2 3.142 Apparent Specific 9.5 2.992 4.75 Gravity 3.084 2.36 2.721 3.142 1.18 2.661 0.6 2.758 2.992 0.3 2.684 3.084 0.15 2.907 2.721 0.075 2.627
2.661 2.758 2.684 2.907 2.627
Saturated Surface—Dry Bulk Specific Physical properties of aggregate. Bulk Specific Gravity
Saturated Surface— 3.066 2.943 Dry Bulk Specific 3.001 Gravity 2.646 3.066 2.602 2.709 2.943 2.635 3.001 2.82 2.646 2.528 2.602 2.709 2.635 2.82 2.528
Gravity 3.031 Bulk Specific 2.917 Gravity 2.961
Water Absorption Rate (%)
2.603 3.031 2.566 2.681 2.917 2.606 2.961 2.776 2.603 2.476
1.17 Water Absorption 0.86 1.35 Rate (%) 1.67 1.17 1.38 1.07 0.86 1.13 1.35 2.14 1.67 2.04
2.566 2.681 2.606 2.776 2.476
1.38 1.07 1.13 2.14 2.04
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Table 4. Physical properties of mineral powder. Table 4. Physical properties of mineral powder.
Project
Unit
Test Results
Apparent specific gravity
g/cm3
Hydrophilic coefficient
—
2.719 2.719 0.19 0.19 100 100 95.1 95.1 87.8 87.8 Noagglomeration agglomeration No 0.68 0.68
Project
Unit
3 Apparent specific gravity g/cm% Moisture content Moisture content % Particle < 0.6 mm Particle size
