Effect of superabsorbent polymers on hydration heat evolution of cementitious materials

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.

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Effects of Mineral Admixtures and Superplasticizer on Controlling Hydration Heat of Cementitious Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.639-640.368 ◽

2013 ◽

Vol 639-640 ◽

pp. 368-371

Author(s):

Qing Huang ◽

Jian Yin ◽

Wei Min Song

Keyword(s):

Fly Ash ◽

Release Rate ◽

Early Stage ◽

Cementitious Materials ◽

Heat Evolution ◽

Hydration Heat ◽

Mineral Admixtures ◽

Evolution Rate ◽

Two Parameters ◽

Peak Value

The effects of mineral admixtures and superplasticizer on reducing the hydration heat of cementitious material were evaluated in this study, and the heat evolution rate and hydration heat were tested as the two parameters to evaluate the effect of improvement. The results showed that the cement partly-replaced with fly ash (FA) and slag (SG) could significantly decrease the release rate of hydration heat on the early stage of hydration, and lower the peak value of the heat evolution rate. The superplasticizer (TJ-Ⅲ) could reduce the hydration heat mainly on the early stage of hydration, and extended the induction period. In comparison with slag, the fly ash had more active effects on reducing the peak value and release rate of hydration heat.

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Synthesis of a New Polycarboxylate at Room Temperature and Its Influence on the Properties of Cement Pastes with Different Supplementary Cementitious Materials

Advances in Civil Engineering ◽

10.1155/2020/8854422 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Shuncheng Xiang ◽

Yingli Gao ◽

Caijun Shi

Keyword(s):

Room Temperature ◽

Autogenous Shrinkage ◽

Drying Shrinkage ◽

Cementitious Materials ◽

Heat Evolution ◽

Hydration Heat ◽

Supplementary Cementitious Materials ◽

Cement Pastes ◽

Binder Ratio ◽

Water Binder Ratio

Three polycarboxylates with different comb structures (i.e., the same degree of polymerization in side chains but different main chains) were synthesized via radical polymerization reaction at room temperature. The effect of polycarboxylates on the surface tension and the flowability in cement pastes was determined. The best product was selected to study its effects on the hydration heat evolution, compressive strength, autogenous shrinkage, and drying shrinkage of cement pastes with different kinds and contents of supplementary cementitious materials. The results showed that with the increase of molar ratio between AA and TPEG to 6 : 1, we could synthesis the best product. When the water-binder ratio was 0.4, with the increase of polycarboxylates, the cement hydration heat evolution had been slowed down, and the more the dosage was, the more obvious the effect was. Adding supplementary cementitious materials to cement under the same experimental conditions also played a mitigation role in slowing down the hydration heat. When the water-binder ratio was 0.3, supplementary cementitious materials could increase the strength of cement by 24.5% in maximum; its autogenous shrinkage and drying shrinkage could be decreased, respectively, by 60.1% and 21.9% in the lowest.

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Characterization of Portland Cement Incorporated with FNS

Advances in Materials Science and Engineering ◽

10.1155/2020/7047549 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9

Author(s):

Won Jung Cho ◽

Min Jae Kim ◽

David Su Vin Lee

Keyword(s):

Tensile Strength ◽

Compressive Strength ◽

Flexural Strength ◽

Cementitious Materials ◽

Heat Evolution ◽

Splitting Tensile Strength ◽

Hydration Heat ◽

Supplementary Cementitious Material ◽

Advantages And Disadvantages ◽

Hydration Characteristics

The potential use of ferronickel slag (FNS) as supplementary cementitious material has been widely researched in recent years. Although much research was carried out on utilizing FNS as a binder, its advantages and disadvantages are still not clear. To properly use FNS as a cement replacement, this paper summarizes the following. (1) Changes expected on the oxide composition of FNS powder are due to the forming ores, fluxing stone, and cooling method. (2) The decreasing of the hydration heat evolution rate was detected by hydration heat evolution test and this is due to the low content of CaO and Al2O3 component in FNS. (3) It was found that the incorporation of FNS forms a dense pore structure more than cement mix and this is due to the secondary hydration reactions. (4) Hydration characteristics of FNS were assessed by pozzolanic reactions unexpectedly detected and incorporation of FNS creates C-S-H gel and hydrotalcite. (5) The development of strength was tested by compressive strength, splitting tensile strength, and flexural strength. From the results, the reduction of compressive strength was detected at an early age but substantially increasing at the long-term curing ages. However, splitting tensile strength and flexural strength of concrete have shown various trends. (6) There is an improvement in the resistance to chloride penetration and sulfate attack while susceptible to carbonation. This is induced by the lowered pH in pore solution due to the reduction of Ca(OH)2 by substituting FNS binder. Finally, (8) ternary blended mixtures with conventional cementitious materials are an option to properly use FNS as a binder.

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