scholarly journals Influence of Glass Powder on Hydration Kinetics of Composite Cementitious Materials

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Xiaolin Chang ◽  
Xinping Yang ◽  
Wei Zhou ◽  
Guoshuai Xie ◽  
Shuhua Liu
Keyword(s):  
Glass Powder ◽  
Isothermal Calorimetry ◽  
Cementitious Materials ◽  
Heat Emission ◽  
Hydration Heat ◽  
Hydration Kinetics ◽  
Period Increase ◽  
Acceleration Period ◽  
Boundary Reaction ◽  
Kinetics Of

The influence of glass powder (GP) on hydration kinetics of composite cementitious materials has been investigated by isothermal calorimetry test and hydration kinetics methods in this paper. The hydration heat emission rate and hydration heat decrease gradually while the induction and acceleration period increase with the increase of GP content. According to Krstulovic-Dabic model, the hydration process of composite cementitious materials containing GP is controlled by a variety of complicated reaction mechanisms, which can be divided into three periods: nucleation and crystal growth (NG), phase boundary reaction (I), and diffusion (D). The NG and I process are shortened after incorporating GP.

scholarly journals Hydration Kinetics of Composite Cementitious Materials Containing Copper Tailing Powder and Graphene Oxide

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2499 ◽  
Author(s):  
Shuhua Liu ◽  
Qiaoling Li ◽  
Xinyi Zhao
Keyword(s):  
Graphene Oxide ◽  
Cementitious Materials ◽  
Heat Evolution ◽  
Hydration Heat ◽  
Hydration Kinetics ◽  
Early Hydration ◽  
Controlling Processes ◽  
Boundary Reaction ◽  
Phase Boundary Reaction ◽  
Cementitious Systems

The hydration heat evolution curves of composite cementitious materials containing copper tailing powder (CT) and graphene oxide (GO) with different contents are measured and analyzed in this paper. The hydration rate and total hydration heat of the composite cementitious materials decrease with the increase of CT dosage, but improve with the increase of CT fineness and GO dosage. The hydration process of the cementitious systems undergoes three periods, namely nucleation and crystal growth (NG), phase boundary reaction (I), and diffusion (D), which can be simulated well using the Krstulovic–Dabic model. The hydration rates of the three controlling processes of the composite cementitious system decrease with the increase of CT content, but improve slightly with the increase of CT fineness. GO enhances the controlling effect of the NG process of the cementitious systems with or without CT, thus promotes the early hydration as a whole.

scholarly journals Effects of Expansive Agents on the Early Hydration Kinetics of Cementitious Binders

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1900 ◽  
Author(s):  
Miao Miao ◽  
Qingyang Liu ◽  
Jian Zhou ◽  
Jingjing Feng
Keyword(s):  
Fly Ash ◽  
Hydration Heat ◽  
Mineral Admixture ◽  
Mineral Admixtures ◽  
Hydration Reaction ◽  
Hydration Kinetics ◽  
Early Hydration ◽  
Expansive Agent ◽  
Mechanical Performances ◽  
Kinetics Of

The addition of expansive agents could overcome the main disadvantages of raw concrete including high brittleness and low tensile strength. Few studies have investigated the early hydration kinetics of expansive cementitious binders, though the findings from the early hydration kinetics are helpful for understanding their technical performances. In this study, mixtures of 3CaO•3Al2O3•CaSO4 and CaSO4 (i.e., ZY-type™ expansive agent) with different proportions of mineral admixtures (e.g., fly ash and slag) were added into cement pastes to investigate the early hydration kinetics mechanism of expansive cementitious binders. Early hydration heat evolution rate and cumulative hydration heat were measured by isothermal calorimeter. Kinetic parameters were estimated based on the Krstulovic–Dabic model and Knudsen equations. Mechanical performances of expansive cementitious binders were tested in order to evaluate if they met the basic requirements of shrinkage-compensating materials in technical use. The early hydration heat released from cementitious binders containing ZY-type™ expansive agent was much greater than that released by pure cement, supporting the idea that addition of the expansive agent would improve the reaction of cement. The early hydration kinetic rates were decreased due to the reactions of the mineral admixture (e.g., fly ash or slag) and the ZY-type™ expansive agent in the cement system. The hydration reaction of cementitious binders containing ZY-type™ expansive agent obeyed the Krstulovic–Dabic model well. Three processes are involved in the hydration reaction of cementitious binders containing ZY-type™ expansive agent. These are nucleation and crystal growth (NG), interactions at phase boundaries (I), and diffusion (D). The 14-day expansion rates of cementitious binders containing ZY-type™ expansive agent are in the range of 2.0 × 10−4 to 3.5 × 10−4, which could meet the basic requirements of anti-cracking performances in technical use according to Chinese industry standard JGJ/T 178-2009. This study could provide an insight into understanding the effects of expansive agents on the hydration and mechanical performances of cementitious binders.

scholarly journals Hydration Kinetics of Portland Cement–Silica Fume Binary System at Low Temperature

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3896 ◽  
Author(s):  
Yao Li ◽  
Yonggang Deng ◽  
Runqing Liu
Keyword(s):  
Binary System ◽  
Low Temperature ◽  
Portland Cement ◽  
Silica Fume ◽  
Rate Constant ◽  
Reaction Order ◽  
Cementitious Materials ◽  
Hydration Kinetics ◽  
K Value ◽  
Kinetics Of

Portland cement–silica fume binary cementitious materials are widely used in engineering construction and have been investigated from micro- to macroscopic aspects. However, the theoretical background on the hydration kinetics of the binary system has not been sufficiently covered in the literature. In this study, the hydration dynamic characteristics of the Portland cement–silica fume binary system curing at low temperature were investigated. Hydration kinetics equations were optimized and a hydration model followed by a computer program was developed to calculate the reaction rate constant K and the reaction order n. This model presented that the hydration process of the binary system at low temperature could be divided into three stages, namely, nucleation and growth (NG), interactions at phase boundaries (I), and diffusion (D). The n values for the binary system varied in the range of 1.2 to 1.6, indicating that the hydration of the binary system at low temperature was a complex elementary reaction. Silica fume can reduce the total heat at the later stage of the hydration and the reaction order n, but increase the heat flow at the accelerating stage and the hydration rate constant K. Low temperature prolonged the hydration induction period, decreased and delayed the secondary exothermic peak, as well as reduced the n and K value.

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