Air entraining admixtures: Mechanisms, evaluations, and interactions

Tunstall, Lori; Ley, M. Tyler; Scherer, George W.

doi:10.1016/j.cemconres.2021.106557

Cited by 96 publications

(45 citation statements)

References 83 publications

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“…Both the amount and quality of these entrapped bubbles are not controlled, which may decrease the mechanical performance of hardened concrete [ 13 , 14 ]. Inhibiting and eliminating the excessive harmful bubbles in fresh concretes has been reported to be advantageous in enhancing the mechanical performance of hardened concretes [ 38 , 39 , 40 , 41 , 42 ]. Table 5 and Figure 9 also show the compressive strengths of the hardened mortar samples mixed with various defoamers after incubation for 28 days.…”

Section: Resultsmentioning

confidence: 99%

Preparation and Properties of Different Polyether-Type Defoamers for Concrete

Qiao

Gao

et al. 2022

Materials

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In this study, a series of polyether-type defoamers for concrete which consist of the same alkyl chain (hydrophobic part) but different polyether chains (hydrophilic part) was prepared, and the structure–property relationship of the defoamers was investigated for the first time. Using oleyl alcohol (OA) as the starting agent (alkyl chain), the polyether defoamers with different polyether chains were prepared by changing the amount and sequence of ethylene oxide (EO) and propylene oxide (PO) units. The properties of different defoamers were tested in aqueous solutions, and fresh and hardened mortars; the structure–property relationship of the defoamers was thus studied. The results indicated that the defoaming capacity of the polyether defoamers decreased with an increased EO amount, and the defoamers linked with both EO and PO units (PO before EO) had a stronger defoaming capacity than those linked with EO only. This study is beneficial for the development and applications of novel synthetic polyether-type defoamers for concrete.

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Section: Resultsmentioning

confidence: 99%

Preparation and Properties of Different Polyether-Type Defoamers for Concrete

Qiao

Gao

et al. 2022

Materials

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“…Such a result is due to the increased volume of water due to freezing. Some of the most effective ways to make concrete resistant to F-T cycles are reducing cement dosage, reducing shrinkage and heat of hydration, keeping the water/cement ratio low, and using air-entraining admixtures [35]- [37]. Since using air-entraining admixtures may cause a significant decrease in the mechanical properties of the concrete, it is recommended to be used under certain limits.…”

Section: Mass Lossmentioning

confidence: 99%

Physical and mechanical properties of pozzolanic materials blended cement mortars before and after the freeze-thaw cycles

FİLİZ>¹,

AKBULUT>

Güler

2023

Bitlis Eren Üniversitesi Fen Bilimleri Dergisi

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Today, Portland cement (PC) production causes a significant release of carbon dioxide (CO2) gas into the atmosphere. The CO2 gases released into the atmosphere create environmental pollution worldwide and prevent current and future generations from living in a cleaner nature. One of the most effective ways of restricting PC use in concrete mixes is to use different types of industrial wastes by replacing them with PC. Using industrial wastes such as fly ash (FA), SF, and MP in concrete mixtures by replacing cement in specific proportions is vital in terms of sustainability. The primary purpose of this study is to examine comparatively the effects of fly ash (FA), silica fume (SF), and marble powder (MP) replaced with cement at the rate of 10%, 20%, and 30% on the flowability, mass loss, and residual compressive strength (RCS) of mortars before and after F-T cycles. According to the results, the effects of FA, SF, and MP on mortars' fresh and hardened properties vary considerably. However, using FA, SF, and MP instead of cement significantly improves the matrix's weak cement/aggregate interface transition zones (ITZ) by showing the filler effect. They contribute considerably to reducing mass losses and increasing the RCS capacities of mortars. Compared to room conditions, the reduction in RCS capacities of the control mortar was 21.32% after 200 F-T cycles, while the decrease in RCS capacities of FA-, SD-, and MP-added mortars was between 7.86 and 19.85%. While the mass loss of the control sample after the 200 F-T cycle is 1.23%, the mass loss of mortars with FA, SF, and MP additives is lower and varies between 0.44% and 1.02%.

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“…Relative reports also proved the strong interaction between AEAs and Ca 2+ improves the frost resistance of concrete at lower additive concentrations 12 . The reduction of surface tension by surfactant‐type AEAs is beneficial for enhancing bubble stability 13 . However, because of the limitations of the molecular structure (simultaneous presence of characteristic structures of surfactant and ion chelation) of AEAs, traditional AEAs can only achieve a single function of either reducing surface tension or binding with Ca 2+ .…”

Section: Introductionmentioning

confidence: 99%

Gelatin‐based air‐entraining agents for ordinary portland cement: Chelate Ca²⁺ and reduce surface tension

Gao,

Tang,

et al. 2024

J of Applied Polymer Sci

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Introducing uniform, stable, and small pores by adding air‐entraining agents (AEAs) is an effective strategy for improving the freeze–thaw resistance and workability of cement concrete materials. In this study, the gelatin with hydrophobic and hydrophilic functional groups was used as an AEA for cement concrete materials and systematically studied its effect on the performance of cement mortar specimens. The results showed that gelatin has a surfactant‐like function and can effectively reduce the surface tension of the gas–liquid interface. In an alkaline environment, Ca2+ ions in cement pore solution chelate with carboxylate ions formed by carboxyl ionization, further enhancing the performance of gelatin‐based AEAs. Thanks to the reduction in surface activity and carboxyl ionization, introducing gelatin increased the porosity of cement mortar specimens from 0.53% to 2.69%. Furthermore, introducing an appropriate amount (>0.1 wt%) of gelatin does not significantly impact the workability or mechanical properties of cement mortar. Based on these characteristics, gelatin has potential as an AEA for cement concrete materials.

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Air entraining admixtures: Mechanisms, evaluations, and interactions

Cited by 96 publications

References 83 publications

Preparation and Properties of Different Polyether-Type Defoamers for Concrete

Preparation and Properties of Different Polyether-Type Defoamers for Concrete

Physical and mechanical properties of pozzolanic materials blended cement mortars before and after the freeze-thaw cycles

Gelatin‐based air‐entraining agents for ordinary portland cement: Chelate Ca²⁺ and reduce surface tension

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Air entraining admixtures: Mechanisms, evaluations, and interactions

Cited by 96 publications

References 83 publications

Preparation and Properties of Different Polyether-Type Defoamers for Concrete

Preparation and Properties of Different Polyether-Type Defoamers for Concrete

Physical and mechanical properties of pozzolanic materials blended cement mortars before and after the freeze-thaw cycles

Gelatin‐based air‐entraining agents for ordinary portland cement: Chelate Ca2+ and reduce surface tension

Contact Info

Product

Resources

About

Gelatin‐based air‐entraining agents for ordinary portland cement: Chelate Ca²⁺ and reduce surface tension