scholarly journals Effects of Nano-CaCO3/Limestone Composite Particles on the Hydration Products and Pore Structure of Cementitious Materials

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Huashan Yang ◽  
Yujun Che
Keyword(s):  
Mechanical Properties ◽  
Pore Structure ◽  
Reaction System ◽  
Cementitious Materials ◽  
Limestone Powder ◽  
Composite Particles ◽  
Gravimetric Analysis ◽  
Hydration Products ◽  
Scanning Calorimetry ◽  
Necked Flask

The agglomeration of nano-CaCO3 (NC) is the largest bottleneck in applications in cementitious materials. If nano-CaCO3 modifies the surface of micron-scale limestone powder (LS), then it will form nano-CaCO3/limestone composite particles (NC/LS). It is known that micron-scale limestone is easily dispersed, and the “dispersion” of NC is governed by that of LS. Therefore, the dispersion of nano-CaCO3 can be improved by the NC/LS in cementitious materials. In this work, the preparation of NC/LS was carried out in a three-necked flask using the Ca(OH)2-H2O-CO2 reaction system. The morphology of NC/LS was observed by a field emission scanning electron microscope (FE-SEM). The effects of NC/LS on the hydration products and pore structure of cementitious materials are proposed. 5% NC/LS was added into cement paste and mortar, and the mechanical properties of the specimens were measured at a certain age. Differential scanning calorimetry (DSC), thermal gravimetric analysis (TG), and backscattered electron imaging (BSE) were conducted on the specimens to investigate the hydration products and pore structure. The properties of specimens with NC/LS were compared to that of control specimens (without NC/LS). The results revealed that NC/LS reduced the porosity and improved the mechanical properties of the cementitious materials.

scholarly journals Utilization of Construction Waste Composite Powder Materials as Cementitious Materials in Small-Scale Prefabricated Concrete

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Cuizhen Xue ◽  
Aiqin Shen ◽  
Yinchuan Guo ◽  
Tianqin He
Keyword(s):  
Mechanical Properties ◽  
Pore Structure ◽  
Composite Powder ◽  
Cementitious Materials ◽  
Small Scale ◽  
Powder Materials ◽  
Hydration Products ◽  
Construction Waste ◽  
Construction And Demolition Wastes ◽  
Composite Powder Material

The construction and demolition wastes have increased rapidly due to the prosperity of infrastructure construction. For the sake of effectively reusing construction wastes, this paper studied the potential use of construction waste composite powder material (CWCPM) as cementitious materials in small-scale prefabricated concretes. Three types of such concretes, namely, C20, C25, and C30, were selected to investigate the influences of CWCPM on their working performances, mechanical properties, and antipermeability and antifrost performances. Also the effects of CWCPM on the morphology, hydration products, and pore structure characteristics of the cement-based materials were analyzed. The results are encouraging. Although CWCPM slightly decreases the mechanical properties of the C20 concrete and the 7 d compressive strengths of the C25 and C30 concretes, the 28 d compressive strength and the 90 d flexural strength of the C25 and C30 concretes are improved when CWCPM has a dosage less than 30%; CWCPM improves the antipermeability and antifrost performances of the concretes due to its filling and pozzolanic effects; the best improvement is obtained at CWCPM dosage of 30%; CWCPM optimizes cement hydration products, refines concrete pore structure, and gives rise to reasonable pore size distribution, therefore significantly improving the durability of the concretes.

scholarly journals Biocomposites of Bio-Polyethylene Reinforced with a Hydrothermal-Alkaline Sugarcane Bagasse Pulp and Coupled with a Bio-Based Compatibilizer

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2158
Author(s):  
Nanci Vanesa Ehman ◽  
Diana Ita-Nagy ◽  
Fernando Esteban Felissia ◽  
María Evangelina Vallejos ◽  
Isabel Quispe ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Water Absorption ◽  
Sugarcane Bagasse ◽  
Thermo Gravimetric Analysis ◽  
Decomposition Temperature ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Cradle To Gate ◽  
Bagasse Pulp

Bio-polyethylene (BioPE, derived from sugarcane), sugarcane bagasse pulp, and two compatibilizers (fossil and bio-based), were used to manufacture biocomposite filaments for 3D printing. Biocomposite filaments were manufactured and characterized in detail, including measurement of water absorption, mechanical properties, thermal stability and decomposition temperature (thermo-gravimetric analysis (TGA)). Differential scanning calorimetry (DSC) was performed to measure the glass transition temperature (Tg). Scanning electron microscopy (SEM) was applied to assess the fracture area of the filaments after mechanical testing. Increases of up to 10% in water absorption were measured for the samples with 40 wt% fibers and the fossil compatibilizer. The mechanical properties were improved by increasing the fraction of bagasse fibers from 0% to 20% and 40%. The suitability of the biocomposite filaments was tested for 3D printing, and some shapes were printed as demonstrators. Importantly, in a cradle-to-gate life cycle analysis of the biocomposites, we demonstrated that replacing fossil compatibilizer with a bio-based compatibilizer contributes to a reduction in CO2-eq emissions, and an increase in CO2 capture, achieving a CO2-eq storage of 2.12 kg CO2 eq/kg for the biocomposite containing 40% bagasse fibers and 6% bio-based compatibilizer.

Research Progress on the Hydration of Portland Cement with Calcined Clay and Limestone

2021 ◽  
Vol 1036 ◽  
pp. 240-246
Author(s):  
Jin Tang ◽  
Su Hua Ma ◽  
Wei Feng Li ◽  
Hui Yang ◽  
Xiao Dong Shen
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Research Progress ◽  
Hydration Reaction ◽  
Hydration Products ◽  
Early Hydration ◽  
Calcined Clay ◽  
Dense Microstructure

The use of calcined clay and limestone as supplementary cementitious materials, can have a certain influence on the hydration of Portland cement. This paper reviewed the influence of limestone and calcined clay and the mixture of limestone and calcined clay on the hydration of cement. Both limestone and calcined clay accelerate the hydration reaction in the early hydration age and enhance the properties of cement. Limestone reacts with C3A to form carboaluminate, which indirectly stabilized the presence of ettringite, while calcined clay consumed portlandite to form C-(A)-S-H gel, additional hydration products promote the densification of pore structure and increase the mechanical properties. The synergistic effect of calcined clay and limestone stabilize the existence of ettringite and stimulate the further formation of carboaluminate, as well as the C-(A)-S-H gel, contributed to a dense microstructure.

The influence of adding long basalt fiber on the mechanical and thermal properties of composites based on poly(oxymethylene)

2018 ◽  
Vol 33 (4) ◽  
pp. 435-450 ◽  
Author(s):  
Patrycja Bazan ◽  
Stanisław Kuciel ◽  
Mariola Sądej
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
Average Length ◽  
Flexural Modulus ◽  
Basalt Fiber ◽  
Charpy Impact ◽  
Mechanical And Thermal Properties ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Atr Spectroscopy

The work has evaluated the possibility of the potential reinforcing of poly(oxymethylene) (POM) by basalt fibers (BFs) and influence of BFs addition on thermal properties. Two types of composites were produced by injection molding. There were 20 and 40 wt% long BFs content with an average length of 1 mm. The samples were made without using a compatibilizer. In the experimental part, the basic mechanical properties (tensile strength, modulus of elasticity, strain at break, flexural modulus, flexural strength, and deflection at 3.5% strain) of composites based on POM were determined. Tensile properties were also evaluated at three temperatures −20°C, 20°C, and 80°C. The density and Charpy impact of the produced composites were also examined. The influence of water absorption on mechanical properties was investigated. Thermal properties were conducted by the differential scanning calorimetry, thermal gravimetric analysis, and fourier transform infrared (FTIR)-attenuation total reflection (ATR) spectroscopy analysis. In order to make reference to the effects of reinforcement and determine the structure characteristics, scanning electron microscopy images were taken. The addition of 20 and 40 wt% by weight of fibers increases the strength and the stiffness of such composites by more than 30–70% in the range scale of temperature. Manufactured composites show higher thermal and dimensional stability in relation to neat POM.

Preparation of vinyl polymer/polyurethane hybrid latex particles and their application in nano-sized vinyl polymer particle/thermoplastic polyurethane blends

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Yanyan Wei ◽  
Chengzhong Zong ◽  
Fufang Wang
Keyword(s):  
Mechanical Properties ◽  
Thermoplastic Polyurethane ◽  
Polymer Particle ◽  
Gravimetric Analysis ◽  
Hybrid Particles ◽  
Scanning Calorimetry ◽  
Latex Particles ◽  
Vinyl Polymer ◽  
Hybrid Latex ◽  
Polyurethane Matrix

AbstractVinyl polymer/polyurethane hybrid latex particles with various compositions were successfully prepared via emulsion polymerization of vinyl monomer in the presence of self-emulsified polyurethane dispersion without using any surfactant. Studies were carried out on polymerization kinetics, characterization of the hybrid particles and the physical properties of nano-sized vinyl polymer particle/thermoplastic polyurethane blends. It was found that the maximum content of vinyl polymer in polyurethane hybrid particles was up to 80 percent and all of the vinyl polymer/polyurethane hybrid particles were less than 120 nm. Infrared spectroscopy, thermal gravimetric analysis and differential scanning calorimetry analysis indicated the influence of vinyl polymer on the polyurethane hybrid particles. With the polyurethane shells outside and, therefore, good compatibility with polyurethane matrix, the hybrid particles can be easily blended into polyurethane matrix. Some unusual changes of dynamic mechanical properties in the low temperature region were found in the blends of hybrid particles and thermoplastic polyurethane. With the addition of only 3%, the mechanical properties of these blends did not show a significant change. This study provided a new method to prepare hybrid particles in the absence of surfactant and made an attempt on application of vinyl polymer/polyurethane hybrid particles in the blending modification

scholarly journals Ink-bottle Effect and Pore Size Distribution of Cementitious Materials Identified by Pressurization–Depressurization Cycling Mercury Intrusion Porosimetry

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1454 ◽  
Author(s):  
Yong Zhang ◽  
Bin Yang ◽  
Zhengxian Yang ◽  
Guang Ye
Keyword(s):  
Pore Structure ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Mercury Intrusion Porosimetry ◽  
Cementitious Materials ◽  
Limestone Powder ◽  
Accurate Estimation ◽  
Mercury Intrusion ◽  
Pore Size Distributions

Capturing the long-term performance of concrete must be underpinned by a detailed understanding of the pore structure. Mercury intrusion porosimetry (MIP) is a widely used technique for pore structure characterization. However, it has been proven inappropriate to measure the pore size distribution of cementitious materials due to the ink-bottle effect. MIP with cyclic pressurization–depressurization can overcome the ink-bottle effect and enables a distinction between large (ink-bottle) pores and small (throat) pores. In this paper, pressurization–depressurization cycling mercury intrusion porosimetry (PDC-MIP) is adopted to characterize the pore structure in a range of cementitious pastes cured from 28 to 370 days. The results indicate that PDC-MIP provides a more accurate estimation of the pore size distribution in cementitious pastes than the standard MIP. Bimodal pore size distributions can be obtained by performing PDC-MIP measurements on cementitious pastes, regardless of the age. Water–binder ratio, fly ash and limestone powder have considerable influences on the formation of capillary pores ranging from 0.01 to 0.5 µm.

Study on Degumming Technology and Properties of Pineapple Leaf Fiber

2014 ◽  
Vol 484-485 ◽  
pp. 70-74
Author(s):  
Yu Ling Zhao ◽  
Zhuo Zhang
Keyword(s):  
Mechanical Properties ◽  
Good Condition ◽  
Fiber Surface ◽  
Relative Strength ◽  
Good Effect ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Advantages And Disadvantages ◽  
Pineapple Leaf Fiber ◽  
Leaf Fiber

This paper analyzes several existing pineapple leaf fiber degumming methods and their advantages and disadvantages and describes its relationship with the degumming from the structure characteristics and chemical properties of pineapple leaf fiber. The author puts forward the pineapple leaf fiber degumming technology should be to "high-quality, efficient, low consumption, low pollution" direction of development, and put forward a new method of degumming. By means of scanning electron microscope, infrared spectroscopy, mechanical properties, thermal gravimetric analysis, differential scanning calorimetry and other means, to study the structure, mechanical properties and thermal properties of pineapple leaf fiber biochemical degumming treatment. The results show that: biochemical degumming can take off the original fiber, fiber surface glue residue, single fiber are glial exist, but the fiber separation in good condition, the fiber surface is smooth; hemicellulose degradation in biochemical degumming process, but did not completely removed; no effect on biochemical degumming of pineapple leaf fiber structure has good effect, degumming the treated fiber; degumming relative strength; fiber still has relatively high heat resistance.

Durability And Microstructure of Pore Reduced Cements(PRC)

1994 ◽  
Vol 370 ◽  
Author(s):  
N.M. Geslin ◽  
D. Israel ◽  
E.E. Lachowski ◽  
D.E. Macphee
Keyword(s):  
Mechanical Properties ◽  
Pore Structure ◽  
Cementitious Materials ◽  
Product Density ◽  
Structure Characteristics ◽  
Pore Properties ◽  
Durability Performance

AbstractThe pore structure characteristics of cementitious materials play an important role in defining their mechanical and durability performance. The mechanical properties of pore reduced cements (PRC) have already been reported [5] as a function of the product density. This paper reports recent data on the durability of PRC and attempts to relate the pore properties of the material to its resistance against deterioration in aggressive environments.

Preparation of epoxy/urethane graft interpenetrating polymer networks and study of mechanical, thermal and morphological properties

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Mehdi Ghafghazi ◽  
Masoud Esfandeh ◽  
Jalil Morshedian
Keyword(s):  
Mechanical Properties ◽  
Polymer Networks ◽  
Weight Ratio ◽  
Interpenetrating Polymer Networks ◽  
Morphological Properties ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Molecular Weights ◽  
Degradation Temperature ◽  
Ft Ir

AbstractThis paper describes the preparation of Epoxy/Urethane (EP/PU) graft interpenetrating polymer networks (g-IPNs) and investigates the effect of EP/PU weight ratio and urethane's prepolymer molecular weight on the mechanical, morphological and thermal properties of the IPN system. Here, g-IPN was prepared by thorough mixing of an isocyanate-terminated urethane prepolymer with an epoxy resin followed by simultaneous curing of the resins. Polytetra hydrofuranate (PTHF), molecular weights (Mw) 1000, 2000 and 3000 g/gmol, was used to prepare urethane prepolymers. EP/PU weight ratios were 75/25, 50/50, 30/70 and 15/85. Disappearance of epoxide and isocyanate functional groups was followed by Fourier Transform Infrared spectroscopy (FT-IR), showing curing of the resins. Differential Scanning Calorimetry (DSC) was used to investigate the glass transition temperature (Tg) of the IPNs. Thermal Gravimetric Analysis (TGA), Dynamic Mechanical Thermal Analysis (DMTA), tensile measurements and Scanning Electron Microscopy (SEM) were used to study thermal, mechanical and morphological properties of the prepared systems. The best mechanical properties were obtained at EP/PU weight ratio 75/25 which also shows a fine and uniformly dispersed morphology. Moreover, at this ratio, with increasing PTHF Mw in the urethane prepolymer, the mechanical properties were improved whereas a decrease was observed in Tg and thermal degradation temperature of g-IPNs.

Mechanical Properties and Microstructure Analysis of Copper Tailings Solidifying with Different Cementitious Materials

2014 ◽  
Vol 878 ◽  
pp. 171-176 ◽  
Author(s):  
Xu Quan Huang ◽  
Hao Bo Hou ◽  
Min Zhou ◽  
Wei Xin Wang
Keyword(s):  
Mechanical Properties ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Calcium Silicate Hydrate ◽  
Steel Slag ◽  
Cementitious Materials ◽  
Cementitious Material ◽  
Hydration Products ◽  
New Type ◽  
Furnace Slag

With new type steel slag-blast furnace slag-fluorgypsum-based cemented material, P O42.5 cement, commonly used cementation agent in China, mechanical properties and microstructure of tailings solidification bodies are studied. The hydration products and morphology tailings concretion body in 60 days are analyzed by SEM and XRD test, which reveals the tailings cementation mechanism solidifying with different cementitious material. Furthermore, a large number of slender bar-like ettringite crystals and filamentous network-like calcium-silicate-hydrate gels bond firmly each other, which is the most important reason why steel slag-blast furnace slag-fluorgypsum base cemented material has the best tailings cementation mechanical properties.

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