Resistance of Concrete with Calcium Stearate Due to Chloride Attack Tested by Accelerated Corrosion

Maryoto, Agus

doi:10.1016/j.proeng.2017.01.363

Cited by 19 publications

(12 citation statements)

References 3 publications

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“…As such, the water transport of AAS is still too high and further works are needed. Ge [21], He [22] and Maryoto [23] highlighted that adding calcium stearate (CaSt) into the PC system can remarkably reduce absorption rates due to formation of hydrophobic films on the surface of hydration products.…”

Section: Introductionmentioning

confidence: 99%

An alternative admixture to reduce sorptivity of alkali-activated slag cement by optimising pore structure and introducing hydrophobic film

Yang

2019

Cement and Concrete Composites

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The high water absorption rate of alkali-activated slag (AAS) cement, which causes concerns to designers and constructors as "long-term" durability comes into question, was addressed using an alternative admixture, calcium stearate (CaSt). The macro-and micro-performance of AAS cement with two levels of CaSt dosage (4 wt%, 8 wt% of slag) were characterised under the water to binder ratio (W/B) ranging from 0.35 to 0.45 and benchmarked against corresponding Portland cement (PC) samples by sorptivity along with compressive strength, porosity, electrical resistivity, pore connectivity, pore size distribution and pore geometries. The interpretation of results showed that CaSt played an instrumental role in pore structure features of AAS and the use of CaSt could significantly reduce its sorptivity, even lower than the corresponding PC samples. It is also found that the recommended usage of CaSt is 4% of slag, beyond which no significant variation in sorptivity can be detected. The performance improvement was caused by two main mechanisms, optimising the pore structure (more entrained pores, less pore connectivity factor and less microcracks) and introduce of the hydrophobic film on the pore surface. One limitation of using CaSt was noted as well. That is, the strength development of AAS can be affected and it can be avoided through modifying mix proportions according to practical requirements. Therefore, CaSt can be used as a chemical admixture for AAS to solve the concern on its high sorptivity behaviour.

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Section: Introductionmentioning

confidence: 99%

An alternative admixture to reduce sorptivity of alkali-activated slag cement by optimising pore structure and introducing hydrophobic film

Yang

2019

Cement and Concrete Composites

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“…Hydrophobic treatment prevents wetting of the concrete's porous structure. A great number of organic additives have been studied as hydrophobic reagents including alkyl-alkoxy silane [5,6], surfactants [7,8], acrylic and polyurethane [6,9]. Concrete carbonation is a process in which carbondioxide reacts with calcium hydroxide [10][11][12] in the cement matrix to form calcium carbonate and water and the reaction stoichiometry is: Ca(OH) 2 + CO 2 → CaCO 3 + H 2 O.…”

Section: Introductionmentioning

confidence: 99%

Hydrophobic Calcium Carbonate for Cement Surface

et al. 2017

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This report describes a novel way to generate a highly effective hydrophobic cement surface via a carbonation route using sodium stearate. Carbonation reaction was carried out at different temperatures to investigate the hydrophobicity and morphology of the calcium carbonate formed with this process. With increasing temperatures, the particles changed from irregular shapes to more uniform rod-like structures and then aggregated to form a plate-like formation. The contact angle against water was found to increase with increasing temperature; after 90 • C there was no further increase. The maximum contact angle of 129 • was obtained at the temperature of 60 • C. It was also found that carbonation increased the micro hardness of the cement material. The micro hardness was found to be dependent on the morphology of the CaCO 3 particles. The rod like structures which caused increased mineral filler produced a material with enhanced strength. The 13 C cross polarization magic-angle spinning NMR spectra gave plausible explanation of the interaction of organic-inorganic moieties.

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“…As shown by some researchers (e.g. Ge [22], He [23] and Maryoto [24]), calcium stearate (CaSt) is one type of admixtures for the PC system which can adjust the hydration and significantly improve water resistance. Inspired by possibilities of achieving analogous results in AAS, our previously work [25] suggested that CaSt is able to reduce the sorptivity of the AAS cement through optimising microstructure and introducing the hydrophobic film.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

The role of calcium stearate on regulating activation to form stable, uniform and flawless reaction products in alkali-activated slag cement

Yang

et al. 2019

Cement and Concrete Composites

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In the course of an investigation on using calcium stearate (CaSt) to improve performance of the alkali-activated slag (AAS) cement, the objective of the present work is to discovery its role in the AAS system. Special interest is devoted to understand the influence of CaSt on the reaction process, reaction products and microstructural features of the AAS cement. To achieve this, isothermal calorimetry, impedance characteristics, infrared spectroscopy, X-ray diffraction, thermogravimetry, nitrogen sorption, mercury intrusion porosimetry and scanning electron microscopy were carried out. According to results obtained, the CaSt has three important effects on the AAS cement. Firstly, it inhibited slag reaction with the activator through decreasing activity of alkalis, whereas the amount of C-(A)-S-H gels in the system depended on the usage of CaSt, because the CaSt could have chemical reactions from the alkali-solution and form similar reaction products. Secondly, there is less sodium and more calcium in reaction products of the CaSt added mix, which improve their stability and uniformity. Finally, microstructure characteristics (e.g. pore size distribution, pore connectivity) are optimised and defects are reduced significantly, when the CaSt is added in the AAS mix.

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Resistance of Concrete with Calcium Stearate Due to Chloride Attack Tested by Accelerated Corrosion

Cited by 19 publications

References 3 publications

An alternative admixture to reduce sorptivity of alkali-activated slag cement by optimising pore structure and introducing hydrophobic film

An alternative admixture to reduce sorptivity of alkali-activated slag cement by optimising pore structure and introducing hydrophobic film

Hydrophobic Calcium Carbonate for Cement Surface

The role of calcium stearate on regulating activation to form stable, uniform and flawless reaction products in alkali-activated slag cement

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