Physicochemical Characteristics and Pore Structure of Cement-Based Materials Subjected to External Multi-Ions Attacks and Drying-Wetting Cycles

2021 ◽  
Author(s):  
Shukai Cheng ◽  
Ziyang Wu ◽  
Xuyong Chen ◽  
Zhonghe Shui ◽  
Jian-Xin Lu
Keyword(s):  
Pore Structure ◽  
Physicochemical Characteristics ◽  
Cement Based Materials

scholarly journals Pore Structure Damages in Cement-Based Materials by Mercury Intrusion: A Non-Destructive Assessment by X-Ray Computed Tomography

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2220 ◽  
Author(s):  
Xiaohu Wang ◽  
Yu Peng ◽  
Jiyang Wang ◽  
Qiang Zeng
Keyword(s):  
Computed Tomography ◽  
Pore Structure ◽  
High Mass ◽  
X Ray ◽  
Quantitative Evidence ◽  
Mercury Intrusion ◽  
Pore Size Distributions ◽  
Cement Based Materials ◽  
Before And After ◽  
X Ray Computed

Mercury intrusion porosimetry (MIP) is questioned for possibly damaging the micro structure of cement-based materials (CBMs), but this theme still has a lack of quantitative evidence. By using X-ray computed tomography (XCT), this study reported an experimental investigation on probing the pore structure damages in paste and mortar samples after a standard MIP test. XCT scans were performed on the samples before and after mercury intrusion. Because of its very high mass attenuation coefficient, mercury can greatly enhance the contrast of XCT images, paving a path to probe the same pores with and without mercury fillings. The paste and mortar showed the different MIP pore size distributions but similar intrusion processes. A grey value inverse for the pores and material skeletons before and after MIP was found. With the features of excellent data reliability and robustness verified by a threshold analysis, the XCT results characterized the surface structure of voids, and diagnosed the pore structure damages in terms of pore volume and size of the paste and mortar samples. The findings of this study deepen the understandings in pore structure damages in CBMs by mercury intrusion, and provide methodological insights in the microstructure characterization of CBMs by XCT.

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 Effective Absorption Capacity Examined by Isothermal Calorimetry: Effect of Pore Structure and Water-to-Cement Ratio

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Joo-Ha Lee ◽  
Do Guen Yoo ◽  
Bo Yeon Lee
Keyword(s):  
Activated Carbon ◽  
Carbon Fibre ◽  
Pore Structure ◽  
Isothermal Calorimetry ◽  
Absorption Capacity ◽  
Cement Ratio ◽  
Effective Absorption ◽  
Water To Cement Ratio ◽  
Cement Based Materials ◽  
Activated Carbon Fibre

The accurate measurement of effective absorption capacity is crucial for highly absorptive materials when they are used within cement-based materials. In this study, a method for examining effective absorption capacity using isothermal calorimetry is reviewed and investigated in detail to accommodate different circumstances. Specifically, the effect of different pore structures and water-to-cement ratios in determining effective absorption capacity is experimentally examined using activated carbon fibre and powdered activated carbon. The results suggest that the method may be suitable for porous materials with micropores but not suitable for those with mesopores. Also, the results indicate that the effective absorption capacity value can change with the water-to-cement ratio used. These findings can be used to find the effective absorption capacity of highly absorptive materials more accurately using the isothermal calorimetry method.

Segmented Fractal Pore Structure in Cement-Based Materials Blended with Dolomite Powder

2021 ◽  
Vol 33 (11) ◽  
pp. 04021317
Author(s):  
Xin Zhang ◽  
Yongqi Wei ◽  
Junqing Zuo ◽  
Yu Luo ◽  
Boyuan Wang ◽  
...  
Keyword(s):  
Pore Structure ◽  
Cement Based Materials

scholarly journals Distribution Map of Frost Resistance for Cement-Based Materials Based on Pore Structure Change

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2509
Author(s):  
Nguyen Xuan Quy ◽  
Takumi Noguchi ◽  
Seunghyun Na ◽  
Jihoon Kim ◽  
Yukio Hama
Keyword(s):  
Prediction Model ◽  
Pore Structure ◽  
Frost Resistance ◽  
Frost Damage ◽  
Structure Change ◽  
Quantitative Prediction ◽  
Weather Data ◽  
Distribution Map ◽  
Cement Based Materials ◽  
Damage Risk

This paper presents a prediction method and mathematical model based on experimental results for the change in pore structure of cement-based materials due to environmental conditions. It focuses on frost damage risk to cement-based materials such as mortar. Mortar specimens are prepared using water, ordinary Portland cement, and sand and the pore structure is evaluated using mercury intrusion porosimetry. New formulas are proposed to describe the relationship between the pore structure change and the modified maturity and to predict the durability factor. A quantitative prediction model is established from a modified maturity function considering the influences of environmental factors like temperature and relative humidity. With this model, the frost resistance of cement-based materials can be predicted based on weather data. Using the prediction model and climate data, a new distribution map of frost damage risk is created. It is found that summer weather significantly affects frost resistance, owing to the change in pore structure of cement-based mortar. The model provides a valuable tool for predicting frost damage risk based on weather data and is significant for further research.

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