Functional kinetic analysis of the effect of admixtures on cement hardening

Usherov-Marshak, A. V.; Kabus, A. V.

doi:10.1134/s0020168516040129

Cited by 9 publications

(5 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Their introduction can lead to a significant increase of cement setting times and a decrease in the rate of concrete strength gain [10] or have almost no effect on the hydration process, depending on the type of SRA [11]. The effect of additives on the hydration kinetics of Portland cement was determined by the temperature method in a thermal calorimeter [12,13]. Cement-sand mortar compositions with different contents of cement and additives were simultaneously mixed at a temperature of 20 °C for 3 minutes, then they were placed in 0.5 liter containers.…”

Section: Methodsmentioning

confidence: 99%

“…Figure 6 show that the introduction of the polycarboxylate-based superplasticizer in an amount of 1% in SP mix significantly reduces the intensity of the temperature maximum compared to the control (Ref mortar) by reducing the cement consumption, while the duration of the induction period remains almost unchanged. This makes it possible to use high concentrations of the additive without the risk of a significant increase in the induction period with a prolonged slowdown in hydration processes [12,13], and due to the effective action of polycarboxylate superplasticizers, to reduce cement consumption by 20-25% or more.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

The effect of admixtures on hydration kinetics, shrinkage, and strength of HPC

Sinyakin,

Rozmus,

Hurkalenko

et al. 2024

IOP Conf. Ser.: Earth Environ. Sci.

View full text Add to dashboard Cite

The paper investigates the impact of admixtures on the properties of high-performance concrete (HPC). A series of test were conducted to evaluate the influence of the studied additives and their combinations on drying and autogenous shrinkage, thermal kinetics and strength of cement pastes, mortars and concretes. It is shown, that replacing part of the cement with silica fume has no significant impact on drying shrinkage. The study demonstrates that polycarboxylate-based superplasticizer and shrinkage reducing admixture (SRA) containing neopentyl glycol enhance fresh concrete workability, produce hardened concrete with high strength and durability, and reduce early-age shrinkage in HPC by up to 3 times. The findings reveal that the use of SRA admixture provides a stable effect only at a dosage above 1 wt.% in HPC, where the amount of binder significantly affects drying shrinkage. Results indicate, that combined action of 1.5% of SRA and 0.6 kg/m3 of polypropylene microfibers allows to obtain 40% lower drying shrinkage compared to non-modified HPC.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

The effect of admixtures on hydration kinetics, shrinkage, and strength of HPC

Sinyakin,

Rozmus,

Hurkalenko

et al. 2024

IOP Conf. Ser.: Earth Environ. Sci.

View full text Add to dashboard Cite

show abstract

“…We estimated the effectiveness of the influence of SAS additives on the processes of structure formation of ASC with the help of known thermokinetic criteria [41]:…”

Section: Methods For Studying the Effectiveness Of Modifying Additives On The Properties Of Alkali-activated Slag Cementmentioning

confidence: 99%

Comparison of influence of surfactants on thermokinetic characteristics of alkali-activated slag cement

Kryvenko

Rudenko

Konstantynovskyi

2021

EEJET

View full text Add to dashboard Cite

Increasing the durability of concrete and reinforced concrete structures according to the criterion of crack resistance is a relevant task of construction materials science. To solve this task, this paper proposes effective solutions for adjusting thermofinite characteristics of alkali-activated slag cement (ASC) by using surfactants of various chemical nature in order to control the thermally-stressed state of concrete based on it (ASC concrete). The method of calorimetry was applied to show that the problematic issue is to adjust the structure formation of ASC by anion-active surface-active substances based on complex polyesters. This is predetermined by the instability of the molecular structure of surfactants in the hydration environment of ASC due to the destruction of complex ester bonds as a result of alkaline hydrolysis. Thermokinetic analysis has demonstrated the effectiveness of using anion-active surfactants, which do not contain ester bonds, as regulators of crack resistance of ASC concrete. Simple polyesters and multi-atom alcohols provide the ability to adjust the duration of the induction period while ensuring the required completeness of ASC hydration within a time frame. The effectiveness of cation-active surface-active substances has been shown, which are characterized by the stability of the molecular structure in the hydration environment of ASC and an increased level of adsorbing capacity. The decrease in the effectiveness of surface-active substances has been shown, in terms of the effect on the heat release of ASC, in the following series: alkaline salt of carboxylic acid>salt of the quaternary ammonium compound>simple polyester> polyalcohol>complex polyester. The reported results are important in view of the possibility of effective adjustment of ASC heat release by influencing the structure formation of surfactant with a certain molecular arrangement in order to predictably reduce crack formation in a thermally-stressed state and a corresponding increase in the durability of structures

show abstract

“…The optimal concentrations of additives were chosen taking into account their effect on concrete hardening and compatibility with cements [12]. The consumption of components is based on the actual density of concrete mixtures.…”

Section: Methodsmentioning

confidence: 99%

Estimation of corrosion resistance of modifying concrete in a solution of sulfuric acid

2018

View full text Add to dashboard Cite

This study presents the test results of 8 concrete series in 5% sulfuric acid solution for 28, 56 and 180 days. Each series was made using two mixtures based on CEM II/A-S 32.5 and CEM III/A 32.5 cements. Modification of the properties of concrete was obtained by the introduction of superplasticizer, silica fume, complex of structure modifier and hydrophobic admixture. The water-binder ratio varied from 0.27 to 0.63, the compressive strength was 26 to 83 MPa, and water absorption from 3.4 to 8.4 %. Samples of test cubes (10x10x10 cm) and test beam (16x4x4 cm) were prepared to immersion in the acid solution. The assessment of corrosion resistance was carried out on the weight loss and strength of concrete in relation to the initial value of 28 days. The obtained results showed that the surface layer of concrete in all samples was destroyed after 28 days of exposure. The deterioration of the corrosion resistance of modified concrete in relation to ordinary concrete without additives was observed regardless of the type of cement. An exception was a series of concrete, which had a water-binder ratio of 0.27–0.28 and a compressive strength of 77–83 MPa.

show abstract

Functional kinetic analysis of the effect of admixtures on cement hardening

Cited by 9 publications

References 3 publications

The effect of admixtures on hydration kinetics, shrinkage, and strength of HPC

The effect of admixtures on hydration kinetics, shrinkage, and strength of HPC

Comparison of influence of surfactants on thermokinetic characteristics of alkali-activated slag cement

Estimation of corrosion resistance of modifying concrete in a solution of sulfuric acid

Contact Info

Product

Resources

About