Rheological Properties of Bitumen with Powder Rubber Modifier Obtained by High-Temperature Shear Grinding

The aims of this paper are to prepare disintegrated high volume crumb rubber asphalt (DHVRA) with low viscosity, good workability and low-temperature performance by adding disintegrating agent (DA) in the preparation process, and to further analyze the disintegrating mechanism and evaluated high-temperature and low-temperature rheological properties. To obtain DHVRA with excellent comprehensive performance, the optimum DA dosage was determined. Based on long-term disintegrating tests and the Fluorescence Microscopy (FM) method, the correlations between key indexes and crumb rubber (CR) particle diameter was analyzed, and the evaluation indicator and disintegrating stage division standard were put forward. Furthermore, Fourier transform infrared spectroscopy (FT-IR) and Gel Permeation Chromatography (GPC) was used to reveal the reaction mechanism, and the contact angle test method was adopted to evaluate the surface free energy (SFE). In addition, the high-temperature and low-temperature rheological properties were measured, and the optimum CR content was proposed. Results indicated that the optimum DA dosage was 7.5‰, and the addition of DA promoted the melt decomposition of CR, reduced the viscosity and improved the storage stability. The 135 °C rotational viscosity (RV) of DHVRA from mixing for 3 h could be reduced to 1.475 Pa·s, and the softening point difference was even less than 2 °C. The linear correlation between 135 °C RV and the diameter of CR particle in rubber asphalt system was as high as 0.968, and the viscosity decay rate (VDR) was used as the standard to divide the disintegrating process into a fast disintegrating stage, stable disintegrating stage and slight disintegrating stage. Compared to common rubber asphalt (CRA), DHVRA has an absorption peak at 960 cm−1 caused by trans olefin = C-H, and higher molecular weight and polar component of surface energy. Compared with CRA, although the high-temperature performance of DHVRA decreases slightly, the low-temperature relaxation ability can be greatly improved.

Download Full-text

High-temperature rheological properties of asphalt binders modified with recycled low-density polyethylene and crumb rubber

Construction and Building Materials ◽

10.1016/j.conbuildmat.2021.123852 ◽

2021 ◽

Vol 298 ◽

pp. 123852

Author(s):

Gabriel Macêdo Duarte ◽

Adalberto Leandro Faxina

Keyword(s):

High Temperature ◽

Rheological Properties ◽

Crumb Rubber ◽

Asphalt Binders ◽

Low Density Polyethylene ◽

Low Density ◽

Recycled Low Density Polyethylene

Download Full-text

Carbon Nanomaterials for Enhancing the Thermal, Physical and Rheological Properties of Asphalt Binders

Materials ◽

10.3390/ma14102585 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2585

Author(s):

Zhelun Li ◽

Xin Yu ◽

Yangshi Liang ◽

Shaopeng Wu

Keyword(s):

High Temperature ◽

Rheological Properties ◽

Carbon Nanomaterials ◽

Asphalt Binders ◽

Snow Melting ◽

Temperature Performance ◽

Unique Nature ◽

Application Potential ◽

Urban Heat ◽

Two Parameters

Effective thermal conduction modification in asphalt binders is beneficial to reducing pavement surface temperature and relieving the urban heat island (UHI) effect in the utilization of solar harvesting and snow melting pavements. This study investigated the performance of two nanometer-sized modifiers, graphene (Gr) and carbon nanotubes (CNTs), on enhancing the thermal, physical and rheological properties of asphalt binders. Measurements depending on a transient plant source method proved that both Gr and CNTs linearly increased the thermal conductivity and thermal diffusivity of asphalt binders, and while 5% Gr by volume of matrix asphalt contributed to 300% increments, 5% CNTs increased the two parameters of asphalt binders by nearly 72% at 20 °C. Meanwhile, a series of empirical and rheological properties experiments were conducted. The results demonstrated the temperature susceptibility reduction and high-temperature properties promotion of asphalt binders by adding Gr or CNTs. The variation trends in the anti-cracking properties of asphalt binders modified by Gr and CNTs with the modifier content differed at low temperatures, which may be due to the unique nature of Gr. In conclusion, Gr, whose optimal content is 3% by volume of matrix asphalt, provides superior application potential for solar harvesting and snow melting pavements in comparison to CNTs due to its comprehensive contributions to thermal properties, construction feasibility, high-temperature performance and low-temperature performance of asphalt binders.

Download Full-text

Nanoemulsion with Controlled Rheology under Different Temperature for Effective Removal of Oil-based Drilling Fluid in Offshore Drilling

10.1115/omae2021-62851 ◽

2021 ◽

Author(s):

Renzhou Meng ◽

Chengwen Wang ◽

Xiliang Dong ◽

Chao Xiong

Keyword(s):

High Temperature ◽

Low Temperature ◽

Rheological Properties ◽

Drilling Fluid ◽

Offshore Drilling ◽

Emulsion Droplets ◽

Effective Removal ◽

Engineering Requirement ◽

Important Means ◽

The Stability

Abstract Oil-based drilling fluid (OBDF) is an important means for offshore drilling, but it would affect the cementing quality. Nanoemulsions shows potential for OBDF removal, but how to prepare nanoemulsion meeting the engineering requirement is lack of good understanding. Moreover, nanoemulsions usually behave badly under low/high temperature, which would restrict the application. Revealing removal mechanisms of nanoemulsion and improving nanoemulsion stability at different temperature are of great significance. The nanoemulsion could rapidly spread on the wellbore surfaces, cause the adhering OBDF to curl into little droplets, and solubilize the removed OBDF. The removal efficiency can reach more than 98%. Low temperature and higher concentration of dispersed phase both increased the viscosity of nanoemulsions stabilized by surfactants. PEGs can induce the bridging of emulsion droplets at low temperature, leading to significant increase of nanoemulsions viscoelasticity at low temperature (around 5°C). To control the rheological properties of nanoemulsions, a hydrophobic association polymer, HAAP, was proposed. Nanoemulsions containing HAAP does not gel at low temperature (< 15°C). And the viscoelasticity of nanoemulsions increased slightly when the temperature is higher than 70°C because of the thermoassociating behavior of polymer, which can ensure the stability of the nanoemulsions at high temperature. This paper is helpful to establish a generic route for preparing nanoemulsions with controlled rheological properties under different temperature, which is benefit for their applications in offshore.

Download Full-text

Improving the rheological properties of water-based calcium bentonite drilling fluids using water-soluble polymers in high temperature applications

Journal of Polymer Engineering ◽

10.1515/polyeng-2021-0205 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Jinliang Liu ◽

Fengshan Zhou ◽

Fengyi Deng ◽

Hongxing Zhao ◽

Zhongjin Wei ◽

...

Keyword(s):

High Temperature ◽

Rheological Properties ◽

Apparent Viscosity ◽

Drilling Fluid ◽

Shear Thickening ◽

Water Soluble ◽

Drilling Fluids ◽

Drilling Depth ◽

Filtration Loss ◽

Calcium Bentonite

Abstract Most of bentonite used in modern drilling engineering is physically and chemically modified calcium bentonite. However, with the increase of drilling depth, the bottom hole temperature may reach 180 °C, thus a large amount of calcium bentonite used in the drilling fluid will be unstable. This paper covers three kinds of calcium bentonite with poor rheological properties at high temperature, such as apparent viscosity is greater than 45 mPa·s or less than 10 mPa·s, API filtration loss is greater than 25 mL/30 min, which are diluted type, shear thickening type and low-shear type, these defects will make the rheological properties of drilling fluid worse. The difference is attributed to bentonite mineral composition, such as montmorillonite with good hydration expansion performance. By adding three kinds of heat-resistant water-soluble copolymers Na-HPAN (hydrolyzed polyacrylonitrile sodium), PAS (polycarboxylate salt) and SMP (sulfomethyl phenolic resin), the rheological properties of calcium bentonite drilling fluids can be significantly improved. For example, the addition of 0.1 wt% Na-HPAN and 0.1 wt% PAS increased the apparent viscosity of the XZJ calcium bentonite suspension from 4.5 to 19.5 mPa·s at 180 °C, and the filtration loss also decreased from 20.2 to 17.8 mL.

Download Full-text

Rheological properties of cholesteric liquid crystals as lubricant additives

International Journal of Modern Physics B ◽

10.1142/s0217979219500140 ◽

2019 ◽

Vol 33 (05) ◽

pp. 1950014 ◽

Cited By ~ 1

Author(s):

A. Bindu Madhavi ◽

S. Sreehari Sastry

Keyword(s):

Shear Rate ◽

Rheological Properties ◽

Loss Modulus ◽

Flow Behavior ◽

Lubricant Additives ◽

Rheological Parameters ◽

Practical Applications ◽

Phase Transition Temperatures ◽

Frequency Independent ◽

Temperature Shear

Rheological properties of Cholesteryl n-valerate, Cholesteryl decanoate and Cholesteryl myristate which are esters of cholesterol have been studied. Phase transition temperatures and rheological parameters such as viscosity, elastic modulus G[Formula: see text], loss modulus G[Formula: see text] as functions of temperature, shear rate and time are investigated. In frequency sweep test, a higher transition crossover region has occurred for Cholesteryl myristate, whereas for Cholesteryl n-valerate a frequency-independent plateau prevailed for both the moduli. The occurrence of blue phase in Cholesteryl decanoate during temperature sweep measurements is an indication for the rheological support. The results for steady state have informed that cholesteric esters are having non-Newtonian flow behavior in their respective cholesteric phases. The power-law model has explained well the shear rate dependence of shear stress. A few practical applications of these esters as lubricant additives are discussed, too.

Download Full-text