scholarly journals Surface-Functionalized Nanocelluloses as Viscosity-Modifying Agents in Engineered Cementitious Composites

2021 ◽  
Vol 8 ◽  
Author(s):  
Long Liang ◽  
Junlei Yang ◽  
Guowei Lv ◽  
Zhen Lei ◽  
Xiurong Li ◽  
...  
Keyword(s):  
Surface Oxidation ◽  
Attenuated Total Reflection ◽  
No Oxidation ◽  
Rheological Parameters ◽  
Cementitious Composites ◽  
Gravimetric Analysis ◽  
Oxidation Degree ◽  
Engineered Cementitious Composites ◽  
Degree Of Hydration ◽  
Polyethylene Fiber

This study investigated the feasibility of using nanofibrilliated celluloses (CNF) (0.1% by weight of binder materials) with three oxidation degrees, no oxidation (NCNF), low oxidation (LCNF), and high oxidation (HCNF), as a viscosity-modifying agent (VMA) to develop polyethylene fiber (PE)-engineered cementitious composites (ECC). Attenuated total reflection-Fourier transform infrared (ATR-FTIR), dynamic light scattering (DLS), and zeta potential were performed to characterize the properties of the CNF with different oxidation degrees. More stable CNF suspensions could be obtained due to the increasing oxidation degree. Rheology tests showed that CNF replacing VMA could modify the plastic viscosity and yield stress of the fresh matrices. With increasing the oxidation degree of CNF, a significant enhancement was seen for the rheological parameters. It was conducted that CNF could increase the compressive strength, the tensile stress, the nominal flexural strength, and the fracture toughness compared with ECC using VMA, and much higher oxidation degrees yielded higher enhancements (HCNF > LCNF > NCNF). ECC using CNF to replace VMA also achieved ultra-high ductility behavior with the tensile strain of over 8% and the saturated multiple cracking pattern. These finds were supplemented by thermal gravimetric analysis (TGA), which showed that the degree of hydration increased with increasing CNF surface oxidation degree. Additionally, the morphology images of PE fibers were observed by scanning electron microscope (SEM).

scholarly journals Nanofibrillated celluloses for the performance improvement of ultra-high ductility cementitious composites

2021 ◽  
Author(s):  
Long Liang ◽  
Xin Zhang ◽  
Qiaoling Liu ◽  
Xiurong Li
Keyword(s):  
Isothermal Calorimetry ◽  
Peak Stress ◽  
Rheological Parameters ◽  
Cementitious Composites ◽  
High Ductility ◽  
Hydration Kinetics ◽  
Early Hydration ◽  
Degree Of Hydration ◽  
Low Field ◽  
Flexural Tests

Abstract This study explored the effect of nanofibrillated celluloses (CNF), namely 0%, 0.05%, 0.1%, and 0.15% of binders weight, on the hydration, rheology, pore structure, and mechanical properties of ultra-high ductility cementitious composites (UHDCC). The hydration kinetics were conducted with different CNF contents using isothermal calorimetry (IC), showing a retardation effect of CNF on the early hydration of UHDCC matrices at 70 h due to the absorption of CNF on the surface of cement particles. Then, thermogravimetric analysis (TGA) demonstrated that CNF improved the degree of hydration at 28 days due to the formation of the CNF transport of water into unhydrated cement cores. The two rheological parameters, namely the yield stress and plastic viscosity, of the fresh UHDCC matrices increased with the increasing CNF contents. Low-field nuclear magnetic resonance (LF-NMR) analysis, as a non-destructive method, proved that the addition of CNF could reduce the porosity of UHDCC and refine its pore size distribution, and the 8.9–46.1% enhancement in the compressive strength of corresponding specimens was found. Notably, CNF could increase the tensile initial cracking stress by 91.2% and tensile stress by 30.8% of UHDCC, and maintain or increase its over 8% of tensile strain-hardening capacity. The flexural tests also were found a 54.6% increase in the initial stress and a 14.8% increase in the peak stress. As a preliminary, CNF shows crucial promising as a greener nanomaterial to improve the strength and ductility of UHDCC.

scholarly journals Tensile Performance of High Ductility Cementitious Composites With Recycled Powder From C&D Waste

2021 ◽  
Vol 8 ◽  
Author(s):  
Jing Ji ◽  
Huayu Song ◽  
Liangqin Jiang ◽  
Hongguo Ren ◽  
Yunfeng Zhang ◽  
...  
Keyword(s):  
Tensile Properties ◽  
Sem Analysis ◽  
Cementitious Composites ◽  
Environmental Scanning ◽  
Gravimetric Analysis ◽  
High Ductility ◽  
Hydration Kinetics ◽  
Phase Development ◽  
Polyethylene Fiber ◽  
Micro Structures

The effects of recycled powder (RP) on hydration, micro-structures, compressive strength and tensile properties of high-ductility cementitious composites (HDCC) were studied. Three mass ratios of RP ranging from 10, 30 to 60% were employed to partially replace the cement. The hydration kinetics of RP-amended matrix was measured to investigate the influence of RP on the cementitious hydration process and the phase development was quantified by the thermal gravimetric analysis. Mechanical properties, including the compressive and tensile properties of HDCCs were obtained at 28 days. The morphology of reinforced polyethylene fiber at the fracture surface was obtained by the environmental scanning electron microscope (SEM) analysis.

scholarly journals Test research on mechanical properties of engineered cementitious composites

2021 ◽  
Vol 647 ◽  
pp. 012071
Author(s):  
Shuaiyu Wang ◽  
Hongxiu Du ◽  
Jingjing Lv ◽  
Jun Guo ◽  
Guoyang Yue ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cementitious Composites ◽  
Engineered Cementitious Composites
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