Effects of salts and adsorption on the performance of air entraining agent with different charge type in solution and cement mortar

Qiao, Min; Shan, Guangcheng; Chen, Jian; Wu, Shishan; Gao, Nanxiao; Ran, Qianping; Liu, Jiaping

doi:10.1016/j.conbuildmat.2020.118188

Cited by 31 publications

(13 citation statements)

References 24 publications

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“…Qiao et al [ 25 ] previously identified the influence of calcium ions on the surface activity of anionic surfactants. However, no such behavior in terms of the total air content of mortars was observed, even though the calcium concentration among the different cements varied by up to 10%.…”

Section: Discussionmentioning

confidence: 99%

“…The presence of salts in the solution, namely Ca 2+ ions, was determined to weaken the surface activity of anionic surfactants. However, only the total air content was tested, not the air void structure [ 25 ]. Petit et al showed that, to maintain high foam stability, it is necessary to obtain monolayer adsorption of the surfactant on the solid’s surface [ 26 ].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impact of Surfactant and Calcium Sulfate Type on Air-Entraining Effectiveness in Concrete

Sypek¹,

Latawiec²,

Łaźniewska-Piekarczyk

et al. 2022

Materials

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The paper presents the evaluation of the influence of calcium sulfate on the air void microstructure in concrete and its action mechanism depending on the character of the air-entraining agent. Gypsum dehydration has been previously proven to negatively influence the air void structure of air-entrained concrete. Ettringite, nucleating from tricalcium aluminate and calcium sulfate, influences the adsorption and mode of action of anionic-based polycarboxylate ether admixtures. The authors suspected the admixture’s air-entraining mechanism was also affected by these characteristics. Gypsum dehydration was confirmed to influence the air void structure. In the case of the anionic surfactant, the content of air bubbles smaller than 300 µm was lower compared to cement with gypsum and hemihydrate. On the other hand, the content of air voids with a diameter up to 60 µm, which are the most favorable, was higher. The results obtained led to the conclusion that the mechanism of air entrainment was twofold, and in most cases occurred through the lowering of surface tension and/or through the adsorption of surfactant on cement grains. The adsorptive mechanism was proved to be more effective in terms of the total air content and the structure of the air void system. The results and conclusions of the study provide guidelines to determine the proper surfactant type to reduce the risk of improper air entrainment of concrete, and emphasize the importance of gypsum dehydration of cement in the process of air entrainment.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impact of Surfactant and Calcium Sulfate Type on Air-Entraining Effectiveness in Concrete

Sypek¹,

Latawiec²,

Łaźniewska-Piekarczyk

et al. 2022

Materials

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“…The data shows that GO provides additional dimensions to cement and cement-based materials, which can substantially improve the potential of optimizing the microstructure and improving the macroscopic properties of the cement-based composites [12,13]. The development of GO as a nano-reinforcer to modify the properties of cementitious materials has become a new research hotspot [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Study on the Hydration and Physical Properties of Cement by M18 Polycarboxylate Superplasticizer Modified Graphene Oxide

Liao¹,

Li²,

Zhou³

et al. 2023

Journal of Renewable Materials

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Graphene oxide (GO) as a new nano-enhancer in cement-based materials has gained wide attention. However, GO is easy to aggregate in alkaline cement mortar with poor dispersibility. This hinders its application in practical infrastructure construction. In this work, GO-M18 polycarboxylate compound superplasticizer (GM) were obtained by compounding the M18 polycarboxylate superplasticizer with GO solution at different mass ratios. The dispersion of GM in alkaline solution was systematically studied. The phases and functional groups of GM were characterized by XRD and FTIR. The effects of GM on the cement mortar hydration and the formation of microstructure were investigated by measuring the heat of hydration, MIP, TG/DSC, and SEM. The results show that the long-chain structure of the M18 polycarboxylate superplasticizer can increase the interlayer spacing of GO and weaken the force between GO sheets. The modified GO can be uniformly dispersed in the cement slurry. GM can accelerate the early hydration process of cement, which can increase the content of Ca(OH) 2 and decrease the grain size. It can optimize the pore size distribution of cement-based materials, increase the density of harmless and less harmful pores, thereby improving mechanical properties. Such methods can transform traditional cement-based materials into stronger, more durable composites, which prolong the life of cementbased materials and reduce the amount of cement used for later maintenance. This provides an idea for achieving sustainability goals in civil engineering.

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“…Although there have been extensive works dealing with the air-entraining performance, there is a paucity of information on the interaction between solid particles and surfactants due to the limitations of test methods such as surface tension or foam height measurements [ 24 , 25 , 26 ]. Thus, test methods involving solid phases are needed.…”

Section: Introductionmentioning

confidence: 99%

Study of the Air-Entraining Behavior Based on the Interactions between Cement Particles and Selected Cationic, Anionic and Nonionic Surfactants

2020

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The essential role of the air void size distribution in air-entrained cementitious materials is widely accepted. However, how the air-entraining behavior is affected by features such as the molecular structure of air-entraining agents (AEAs), the type of solid particles, or the chemical environment of the pore solution in fresh mortars is still not well understood. Besides, methods to assess the interaction between AEAs and cement particles are limited. Thus, in this study, the air-entraining behaviors of three kinds of surfactant (cationic, anionic, and nonionic) were examined. The general working mechanisms of these surfactants were studied by zeta potential and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. Results indicate that the cationic surfactant entrains improper coarse air voids due to the strong electrical interaction between air bubbles formed by the cationic surfactant and negatively charged cement particles. The anionic surfactant interacts with the positively charged part of cement particles, and thus entrains finer air voids. The interaction between the nonionic surfactant and cement particles is very weak; as a result, the nonionic surfactant entrains the finest and homogeneous air voids.

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Effects of salts and adsorption on the performance of air entraining agent with different charge type in solution and cement mortar

Cited by 31 publications

References 24 publications

Impact of Surfactant and Calcium Sulfate Type on Air-Entraining Effectiveness in Concrete

Impact of Surfactant and Calcium Sulfate Type on Air-Entraining Effectiveness in Concrete

Study on the Hydration and Physical Properties of Cement by M18 Polycarboxylate Superplasticizer Modified Graphene Oxide

Study of the Air-Entraining Behavior Based on the Interactions between Cement Particles and Selected Cationic, Anionic and Nonionic Surfactants

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