scholarly journals Surface Charge Properties of Marble Powder and its Effect on the Formation of Hydrates in Cement Paste

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 914
Author(s):  
Xiaowei Ouyang ◽  
Shida Xu ◽  
Liquan Wang ◽  
Jianzhang Huang
Keyword(s):  
Surface Charge ◽  
Co2 Emission ◽  
Electrostatic Force ◽  
Cement Particle ◽  
Hydration Products ◽  
Early Hydration ◽  
Cement Based Materials ◽  
Marble Powder ◽  
Formation Of Hydrates ◽  
Reducing Energy

Replacing part of cement with waste stone powder can reduce the use of cement, thus reducing energy consumption and CO2 emission. Different stone powders affect the properties of cement-based materials differently. It is important to clarify the effect of the surface properties of the stone powder on the properties of cement-based materials. In this paper, the charge properties of marble powder and its effect on the formation of hydrates were investigated. Zeta potential was used to study the charge properties of the marble surface. Parallelly, the morphology of hydrates on the surface of the cement and marble particles at a very early hydration age was observed by using SEM. Finally, the influence of the surface charge properties of the marble particles on the formation of hydration products of cement was discussed. The results showed that the marble particles have specific adsorption of Ca2+ (chemical adsorption). Therefore, the marble particles in the simulated solution can adsorb a large amount of Ca2+, thus achieving a high potential value and facilitating the formation of hydrates on their surface. However, the adsorption of Ca2+ towards the surface of the cement particle is driven by a relatively weak electrostatic force. Compared with the marble particles, less Ca2+ ions are adsorbed, and thus, fewer hydrates are formed on the surface of cement particles.

Research of Electrical and Hydration Behavior of Phosphoaluminate Cementitious Material

2010 ◽  
Vol 129-131 ◽  
pp. 926-930
Author(s):  
Ming Zhang ◽  
Zhu Ding ◽  
Peng Liu ◽  
Ming Ke Wang ◽  
Feng Xing
Keyword(s):  
Impedance Spectroscopy ◽  
Cementitious Material ◽  
Hydration Process ◽  
Early Age ◽  
Hydration Products ◽  
Micro Structure ◽  
Microstructure Formation ◽  
Early Hydration ◽  
Cement Based Materials ◽  
Acceleration And Deceleration

Electrodeless resistivity and impedance spectroscopy measurement are reliable equipments of test online for monitoring the hydration process of cement-based materials continuously and accurately. Phosphoaluminate cement (PAC) sets quickly and develops high early strength. In order to understand the mechanism, the hydration products and microstructure formation of PAC in early age need to be studied. In the study, early hydration process and impedance spectroscopy characteristics of PAC with different dosage of retarder were investigated. According to the test, resistivity of freshly mixed PAC paste decreases sharply and then rises slowly, some characteristic peaks appear at different hydration stages of PAC, which indicates the hydration process of PAC includes four stages which are dissolution, induction, acceleration and deceleration. Impedance spectroscopy can reflect the change of micro-structure and ion concentribution of PAC matrix by resistance and capacitance.

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.

scholarly journals Mechano-Triboelectric Analysis of Surface Charge Generation on Replica-Molded Elastomeric Nanodomes

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1460
Author(s):  
Myung Gi Ji ◽  
Mohammed Bazroun ◽  
In Ho Cho ◽  
W. Dennis Slafer ◽  
Rana Biswas ◽  
...  
Keyword(s):  
Charge Density ◽  
Surface Charge ◽  
Electrostatic Force ◽  
High Surface ◽  
Interfacial Friction ◽  
Generation Process ◽  
Charge Generation ◽  
Replica Molding ◽  
Force Microscopy ◽  
Triboelectric Charging

Replica molding-based triboelectrification has emerged as a new and facile technique to generate nanopatterned tribocharge on elastomer surfaces. The “mechano-triboelectric charging model” has been developed to explain the mechanism of the charge formation and patterning process. However, this model has not been validated to cover the full variety of nanotexture shapes. Moreover, the experimental estimation of the tribocharge’s surface density is still challenging due to the thick and insulating nature of the elastomeric substrate. In this work, we perform experiments in combination with numerical analysis to complete the mechano-triboelectrification charging model. By utilizing Kelvin probe force microscopy (KPFM) and finite element analysis, we reveal that the mechano-triboelectric charging model works for replica molding of both recessed and protruding nanotextures. In addition, by combining KPFM with numerical electrostatic modeling, we improve the accuracy of the surface charge density estimation and cross-calibrate the result against that of electrostatic force microscopy. Overall, the regions which underwent strong interfacial friction during the replica molding exhibited high surface potential and charge density, while those suffering from weak interfacial friction exhibited low values on both. These multi-physical approaches provide useful and important tools for comprehensive analysis of triboelectrification and generation of nanopatterned tribocharge. The results will widen our fundamental understanding of nanoscale triboelectricity and advance the nanopatterned charge generation process for future applications.

scholarly journals Crossover Effect in Cement-Based Materials: A Review

2019 ◽  
Vol 9 (14) ◽  
pp. 2776 ◽  
Author(s):  
Sumra Yousuf ◽  
Payam Shafigh ◽  
Zainah Ibrahim ◽  
Huzaifa Hashim ◽  
Mohammad Panjehpour
Keyword(s):  
Compressive Strength ◽  
Construction Industry ◽  
Building Materials ◽  
Cement Hydration ◽  
Curing Temperature ◽  
Future Research ◽  
Hydration Products ◽  
Crossover Effect ◽  
Cement Based Materials ◽  
Mineral Compositions

Cement-based materials (CBMs) such as pastes, mortars and concretes are the most frequently used building materials in the present construction industry. Cement hydration, along with the resulting compressive strength in these materials, is dependent on curing temperature, methods and duration. A concrete subjected to an initial higher curing temperature undergoes accelerated hydration by resulting in non-uniform scattering of the hydration products and consequently creating a great porosity at later ages. This phenomenon is called crossover effect (COE). The COE may occur even at early ages between seven to 10 days for Portland cements with various mineral compositions. Compressive strength and other mechanical properties are important for the long life of concrete structures, so any reduction in these properties is of great concern to engineers. This study aims to review existing information on COE phenomenon in CBMs and provide recommendations for future research.

Dispersion and Absorption of SBR Latex in the System of Mono-Dispersed Cement Particles in Water

2013 ◽  
Vol 687 ◽  
pp. 347-353 ◽  
Author(s):  
Xiao Xin Shi ◽  
Ru Wang ◽  
Pei Ming Wang
Keyword(s):  
Cement Hydration ◽  
Single Layer ◽  
Optical Microscope ◽  
Solution Phase ◽  
Environmental Scanning ◽  
Cement Particle ◽  
Microstructure Formation ◽  
Cement Ratio ◽  
Water To Cement Ratio ◽  
Cement Based Materials

This paper investigates the dispersion of cement particles in water at different mix proportions using optical microscope, and the dispersion and absorption of SBR latex in the system of mono-dispersed cement particles in water using environmental scanning electron microscope (ESEM). The results show that the mono-dispersed cement can be well obtained at the water to cement ratio (mw/mc) of 10:1. The ESEM images present that SBR latex is dispersed on the surface of the cement particles as well as the solution phase. SBR latex does not prefer to be absorbed on the cement particles in spite of their opposite electric charge but chooses to be dispersed in the system proportionally. In addition, SBR particles are single-layer absorbed on the surface of cement particles in all the SBR latex to cement ratios (mp/mc). Several SBR particles absorbed on the surface of cement particle get close enough to form groups at the mp/mc of 15% and 20%. The results of this paper provide some bases for analyzing the influence of polymer on cement hydration and the microstructure formation of polymer-modified cement-based materials in a new view.

Physical and Chemical Influence of Polyacrylate Latex on Cement Mortars

2011 ◽  
Vol 261-263 ◽  
pp. 807-811 ◽  
Author(s):  
Ye Tian ◽  
Zong Jin Li ◽  
Hong Yan Ma ◽  
Xian Yu Jin ◽  
Nan Guo Jin
Keyword(s):  
Pore Structure ◽  
Cement Hydration ◽  
Bending Strength ◽  
Mechanical Performance ◽  
Air Entrainment ◽  
Hydration Products ◽  
Cement Mortars ◽  
Cement Based Materials ◽  
Physical And Chemical ◽  
Chemical Influence

In this research, the physical and chemical influence of polyacrylate (PA) latex on cement-based materials were studied using polymer modified mortars with polymer/cement (P/C) ratios of 0%, 5% and 10%. Physically, the mechanical performance of PA latex modified mortars was investigated with compression toughness energy and bending strength. Further more, a comparison of the pore structure and porosity between PA latex modified and unmodified mortars was conducted. The chemical reactions between PA polymer and cement hydrates were clarified with thermogravimetric (TG) analysis. It can be concluded from this research that PA polymer can refine the pore structure of cement mortars and link the cement hydration products together chemically. While, at the same time, PA latex addition can cause air entrainment which will weaken the physical behavior of cement mortars. So there is an optimum P/C ratio to achieve the best mechanical properties. And in this research, the optimum P/C ratio is 5%.

scholarly journals Exploring the Influence Factors of Early Hydration of Ultrafine Cement

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5677
Author(s):  
Yi Shi ◽  
Tao Wang ◽  
Haiyan Li ◽  
Shaoliang Wu
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Isothermal Calorimetry ◽  
Influence Factors ◽  
Particle Diameter ◽  
Curing Temperature ◽  
Strength Development ◽  
Cement Particle ◽  
Early Hydration ◽  
Ultrafine Cement

This work intends to contribute to the understanding of the influence factors of early hydration of ultrafine cement by focusing on the different fineness, different kinds of hardening accelerators, and different curing temperatures. Isothermal calorimetry, thermogravimetry, and X-ray diffraction (XRD) were performed to compare the hydration and chemical evolution of pastes containing accelerators with different fineness and curing temperatures; meanwhile, mechanical properties and water absorption were tested. The results showed that the cement fineness had a significant effect on the early hydration process; the smaller the cement particle size, the higher the early compressive strength. The 24 h compressive strength of ultrafine cement with a particle diameter of 6.8μm could reach 55.94 MPa, which was 118% higher than the reference cement. Water absorption test results indicated that adding 1% Ca(HCOO)2 to ultrafine cement can effectively reduce the water absorption, and it was only 1.93% at 28 d, which was 46% lower than the reference cement. An increase in curing temperature accelerated the activation of ultrafine cement in terms of the strength development rate, and the content of Ca(OH)2 in the ultrafine cement paste could reach 13.09% after being mixed with water for 24 h, which was 22% higher than that of the reference cement.

Utilization of waste marble powder in cement-based materials by incorporating nano silica

2019 ◽  
Vol 211 ◽  
pp. 139-149 ◽  
Author(s):  
Baoguo Ma ◽  
Jie Wang ◽  
Hongbo Tan ◽  
Xiangguo Li ◽  
Lixiong Cai ◽  
...  
Keyword(s):  
Nano Silica ◽  
Cement Based Materials ◽  
Marble Powder

scholarly journals Nanotechnology in Cement-Based Materials: A Review of Durability, Modeling, and Advanced Characterization

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1213 ◽  
Author(s):  
Sen Du ◽  
Junliang Wu ◽  
Othman AlShareedah ◽  
Xianming Shi
Keyword(s):  
Recent Progress ◽  
Cement Hydration ◽  
Advanced Characterization ◽  
Cement Composites ◽  
Hydration Products ◽  
Cement Based Materials ◽  
Rebar Corrosion ◽  
Nanoscale Modeling

In the context of increasing applications of various nanomaterials in construction, this work reviews the renewed knowledge of nanotechnology in cement-based materials, focusing on the relevant papers published over the last decade. The addition of nanomaterials in cement-based materials, associated with their dispersion in cement composites, is explored to evaluate their effects on the resistance of cement-based materials to physical deteriorations, chemical deteriorations, and rebar corrosion. This review also examines the proposed nanoscale modeling of interactions between admixed nanomaterials and cement hydration products. At last, the recent progress of advanced characterization that employs techniques to characterize the properties of cement-based materials at the nanoscale is summarized.

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