scholarly journals Predictive Hydration Model of Portland Cement and Its Main Minerals Based on Dissolution Theory and Water Diffusion Theory

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 595
Author(s):  
Tianqi Qi ◽  
Wei Zhou ◽  
Xinghong Liu ◽  
Qiao Wang ◽  
Sifan Zhang
Keyword(s):  
Portland Cement ◽  
Cement Hydration ◽  
Diffusion Theory ◽  
Moisture Diffusion ◽  
Test Results ◽  
Cement Slurry ◽  
Element Analysis ◽  
Prediction Ability ◽  
Hydration Effect ◽  
Hydration Model

Efficient and accurate cement hydration simulation is an important issue for predicting and analyzing concrete’s performance evolution. A large number of models have been proposed to describe cement hydration. Some models can simulate the test results with high accuracy by constructing reasonable functions, but they are based on mathematical regression and lack of physical background and prediction ability. Other models, such as the famous HYMOSTRUC model and CEMHYD3D model, can predict the hydration rate and microstructure evolution of cement based on its initial microstructure. However, this kind of prediction model also has some limitations, such as the inability to fully consider the properties of cement slurry, or being too complicated for use in finite element analysis (FEA). In this study, the hydration mechanisms of the main minerals in Portland cement (PC) are expounded, and the corresponding hydration model is built. Firstly, a modified particle hydration model of tricalcium silicate (C3S) and alite is proposed based on the moisture diffusion theory and the calcium silicate hydrate (C-S-H) barrier layer hypothesis, which can predict the hydration degree of C3S and alite throughout the age. Taking the hydration model of C3S as a reference, the hydration model of dicalcium silicate (C2S) is established, and the synergistic hydration effect of C3S and C2S is calibrated by analyzing the published test results. The hydration model of tricalcium aluminate(C3A)-gypsum system is then designed by combining the theory of dissolution and diffusion. This model can reflect the hydration characteristics of C3A in different stages, and quantify the response of the hydration process of C3A to different gypsum content, water–cement ratio, and particle size distribution. Finally, several correction coefficients are introduced into the hydration model of the main mineral, to consider the synergistic hydration effect among the minerals to some extent and realize the prediction of the hydration of PC.

scholarly journals Influence of Organic Esters on Portland Cement Hydration and Hardening

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Duan-le Li ◽  
Da-peng Zheng ◽  
Dong-min Wang ◽  
Ji-hui Zhao ◽  
Cheng Du ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Cement Hydration ◽  
Setting Time ◽  
Exothermic Peak ◽  
Hardened Cement ◽  
Test Results ◽  
Trimethyl Phosphate ◽  
Cement Slurry ◽  
Hydration Degree ◽  
Dimethyl Oxalate

This paper investigated the effect of organic compounds with ester groups on the hydration and hardening of cement. The effects of five kinds of organic compounds with ester groups (ethyl acetate, dimethyl oxalate, glyceryl triacetate, trimethyl phosphate, and triethanolamine borate) on hydration heat, hydration degree, setting time, mechanical properties, microstructure, and pore structure of hardened cement slurry were studied. The test results showed that esters can make the end time of cement hydration induction longer and delay the occurrence of the second exothermic peak. Also, the effect of five kinds of esters on the hydration and hardening of cement was basically followed by TG> TB> DMO> EAC> TMP. In terms of molecular structure, for organic compounds containing only ester groups, the higher the number of ester groups, the greater the effect on the hydration of cement. The introduction of other functional groups (such as phosphate or borate) will influence the effect of the esters.

Modeling of hydration reactions to predict the properties of slag blended concrete

2014 ◽  
Vol 41 (5) ◽  
pp. 421-431
Author(s):  
Xiao-Yong Wang ◽  
Ki-Bong Park
Keyword(s):  
Portland Cement ◽  
Cement Hydration ◽  
Blended Cement ◽  
Numerical Procedure ◽  
Reaction Model ◽  
Heat Evolution ◽  
Mineral Admixture ◽  
Temperature History ◽  
Granulated Blast Furnace Slag ◽  
Hydration Model

The granulated blast furnace slag is commonly blended with Portland cement or clinker to produce slag blended cement after being ground to the fineness comparable to Portland cement. Hydration of slag-blended cement is much more complex than that of ordinary Portland cement because of the mutual interactions between the cement hydration and the slag reaction. In this paper, by considering the production of calcium hydroxide in cement hydration and its consumption in the reaction of slag, a numerical procedure is proposed to simulate the hydration of concrete containing slag. The numerical procedure includes two sub components, a cement hydration model and a slag reaction model. The heat evolution rate of slag concrete is determined from the contributions of the cement hydration and the slag reaction. Furthermore, the temperature history in hardening blended concrete is evaluated by combining the proposed numerical procedure with a finite element method. The proposed model is verified through experimental data on concrete with different water–cement ratios and mineral admixture substitution ratios.

EFFECT OF VISCOSITY MODIFIER ADMIXTURE ON PORTLAND CEMENT HYDRATION

2018 ◽  
Author(s):  
Stefan C. Figueiredo ◽  
Oğuzhan Çopuroğlu ◽  
Erik Schlangen
Keyword(s):  
Portland Cement ◽  
Cement Hydration ◽  
Viscosity Modifier ◽  
Portland Cement Hydration

Finite Element Analysis of Reinforced Concrete Beams with Exterior FRP Shell

2011 ◽  
Vol 243-249 ◽  
pp. 1461-1465
Author(s):  
Chuan Min Zhang ◽  
Chao He Chen ◽  
Ye Fan Chen
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Contact Interface ◽  
Accurate Calculation ◽  
Element Analysis

The paper makes an analysis of the reinforced concrete beams with exterior FRP Shell in Finite Element, and compares it with the test results. The results show that, by means of this model, mechanical properties of reinforced concrete beams with exterior FRP shell can be predicted better. However, the larger the load, the larger deviation between calculated values and test values. Hence, if more accurate calculation is required, issues of contact interface between the reinforced concrete beams and the FRP shell should be taken into consideration.

Moisture Diffusion in Unsaturated Polyester Composites Reinforced with Macambira Natural Fiber: A Finite-Volume Approach

2015 ◽  
Vol 3 ◽  
pp. 89-101
Author(s):  
V.C. de Almeida Cruz ◽  
J.M.P.Q. Delgado ◽  
A.G. Barbosa de Lima ◽  
M.M. Silva Nóbrega ◽  
L.H. de Carvalho ◽  
...  
Keyword(s):  
Water Absorption ◽  
Polymer Composites ◽  
Finite Volume ◽  
Natural Fiber ◽  
Diffusion Theory ◽  
Unsaturated Polyester ◽  
Moisture Diffusion ◽  
Moisture Distribution ◽  
Vegetable Fibers ◽  
Finite Volume Approach

This paper presents a theoretical and experimental study about water absorption in unsaturated polyester polymer composites reinforced with vegetable fibers, with particular reference to macambira fiber. A mathematical modeling based on the liquid diffusion theory has been proposed and numerical procedures using the finite volume technique are presented and discussed. Results of the water absorption kinetic and moisture content distribution for the polymer composites are shown and analyzed. The knowledge of moisture distribution inside the composite is essential for determination of areas that may show delamination problems (moisture induced degradation) due to the weakness of the fiber-matrix interface and consequently reduction in the mechanical properties of the composites.

Experimental and theoretical study of sandwich composites with Z-pins under quasi-static compression loading

2021 ◽  
pp. 136943322110073
Author(s):  
Erdem Selver ◽  
Gaye Kaya ◽  
Hussein Dalfi
Keyword(s):  
Vinyl Ester ◽  
Failure Modes ◽  
Critical Role ◽  
Sandwich Composites ◽  
Test Results ◽  
Compressive Properties ◽  
Element Analysis ◽  
Static Compression ◽  
Quasi Static Compression ◽  
Good Agreement

This study aims to enhance the compressive properties of sandwich composites containing extruded polystyrene (XPS) foam core and glass or carbon face materials by using carbon/vinyl ester and glass/vinyl ester composite Z-pins. The composite pins were inserted into foam cores at two different densities (15 and 30 mm). Compression test results showed that compressive strength, modulus and loads of the sandwich composites significantly increased after using composite Z-pins. Sandwich composites with 15 mm pin densities exhibited higher compressive properties than that of 30 mm pin densities. The pin type played a critical role whilst carbon pin reinforced sandwich composites had higher compressive properties compared to glass pin reinforced sandwich composites. Finite element analysis (FE) using Abaqus software has been established in this study to verify the experimental results. Experimental and numerical results based on the capabilities of the sandwich composites to capture the mechanical behaviour and the damage failure modes were conducted and showed a good agreement between them.

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