Sulfate diffusion in calcium sulphoaluminate mortar

Hou, Wei; Liu, Zanqun; He, Fuqiang; Huang, Ju; Zhou, Jin

doi:10.1016/j.conbuildmat.2019.117312

Cited by 19 publications

(8 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The evaporation and immersion zone of the specimens were cut according to the position shown in Figure 2 a. The samples were saturated with water in vacuum to a constant weight [ 25 ] prior to test. A MicroMR12-025 manufactured by Newmark Electronic Technology Ltd., California, USA was used, with a resonance frequency of 11.793 MHz, a magnet temperature control of 35.00 ± 0.02 °C, and a probe coil diameter of 25 mm.…”

Section: Methodsmentioning

confidence: 99%

The Damage Performance of Uncarbonated Limestone Cement Pastes Partially Exposed to Na2SO4 Solution

Cui

Pei²,

Huang

et al. 2022

Materials

Self Cite

View full text Add to dashboard Cite

Pore structure and composition of cement paste are the main two factors in controlling the sulfate attack on concrete, but the influence of carbonization on pore structure and composition is often ignored in sulfate attack. Therefore, will the damage performance of concrete partially exposed to sulfate solution be different avoiding the alterations of pore structure and composition due to carbonation? In this paper, the cement pastes were partially immersed in 5 wt. % sodium sulfate solution, with N2 as protective gas to avoid carbonation (20 ± 1°C, RH 65 ± 5%). Pore structures of cements were changed by introducing different contents of limestone powders (0 wt. %, 10 wt. %, 20 wt. %, and 30 wt. %) into cement pastes. The damage performance of the specimens was studied by 1H NMR, XRD and SEM. The results showed that the immersion zone of pure cement paste under N2 atmosphere remained intact while serious damage occurred in the evaporation zone. However, the damage of cement + limestone powders pastes appeared in the immersion zone rather than in the evaporation zone and cement pastes containing more limestone were more severely damaged. Compositional analysis suggested that the damage of the evaporation zone or the immersion zone was solely caused by chemical attack where substantial amount of gypsums and ettringites were filled in the pore volumes. Introduction of limestone powders led to the increase of the pore sizes and porosity of cement pastes, causing the damage occurred in the immersion zone not in the evaporation zone.

show abstract

Section: Methodsmentioning

confidence: 99%

The Damage Performance of Uncarbonated Limestone Cement Pastes Partially Exposed to Na2SO4 Solution

Cui

Pei²,

Huang

et al. 2022

Materials

Self Cite

View full text Add to dashboard Cite

show abstract

“…In fact, SAC has been accepted as an eco-friendly cementitious material due to lower energy consumption and less CO 2 emission than PC [26][27][28][29]. However, SAC's cost is higher than PC due to costly raw material, and SAC's late strength usually develops slowly or even decreases slightly because the hydrated product ettringite is easy to decompose or transform, limiting its wide application in engineering [30].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Micro-Iron Ore Tailings by Wet-Grinding and Its Application in Sulphoaluminate Cement

Yang¹,

Chen²,

Sun³

et al. 2022

Journal of Renewable Materials

View full text Add to dashboard Cite

Herein, micro iron ore tailings (micro-IOTs) were prepared by wet-grinding and applied to improve sulphoaluminate cement (SAC) performance. The physicochemical properties of micro-IOTs were investigated by particle size analysis, XRD, and XPS. The hydrates trait and the hydration mechanism of micro-IOTs-SAC composite were studied by XRD, TGA, MIP, and SEM. The results demonstrated that micro-IOTs with an average grain diameter of 517 nm could be obtained by wet-grinding. The setting time of SAC gradually decreased with increasing micro-IOTs content. By adding 2% micro-IOTs, the compressive strengths of SAC pastes were enhanced about 22% and 10% at 4 h and 28 d, respectively. Moreover, the addition of micro-IOTs accelerated ettringite precipitation and changed its morphology, resulting in early strength improvement of the binary system. And increased later strength by micro-IOTs was closely related to the high content of AH 3 , fine pore structure, and high hydration degree of SAC. The findings suggested one new approach to utilize iron ore tailings in cementbased materials.

show abstract

“…It has become increasingly popular in civil engineering nowadays because of its rapid hydration speed, high early strength [3], high impermeability [4,5] and sulfate corrosion resistance [4,6], lower energy consumption [7,8], and lower CO 2 emissions during the calcination process of cement clinkers [6], as well as its low drying shrinkage and low solution alkalinity [9]. Ettringite and aluminum gel are the main hydration products of CSA cement produced via the chemical reaction shown in equation (1), which has good corrosion resistance against sulfate attack [10], where the absence of calcium hydroxide is another advantage for CSA in sulfate environment. e primary mechanism of sulfate attack is the chemical interaction between sulfate ions and hydration products [11].…”

Section: Introductionmentioning

confidence: 99%

“…erefore, the usual approaches to create sulfateresisting concrete are improving the permeability to stop the permeation of sulfate ions and controlling the chemical composition of cement to decrease the unfavorable raw materials [10]. When there is calcium hydroxide in the hydration products of Portland cement, Ca(OH) 2 will react with the sulfate ions in seawater to create gypsum, which is shown in equation (2).…”

Section: Introductionmentioning

confidence: 99%

“…w/c ratio is one of the most fundamental parameters in concrete mixture proportioning [16] as excessive water causes strength reduction, while insufficient water incurs poor workability [17]. Hou et al [10] found that the CSA cement with a w/c ratio of 0.5 had a much greater diffusion coefficient of sulfate ions than the CSA with a w/c ratio of 0.3. Wang et al [18] also concluded that a lower w/c provides a more obvious increase in the strength.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of Water‐Cement Ratio and Type of Mixing Water on the Early Hydration Performance of Calcium Sulphoaluminate (CSA) Cement

Wang

Song

2021

Advances in Materials Science and Engineering

View full text Add to dashboard Cite

The present work studies the influence of water-cement ratio and types of mixing water on the hydration process and microstructure of calcium sulphoaluminate (CSA) cement. Experimental tests on the setting time, physical properties, compressive strength, chemical shrinkage, X-ray diffraction (XRD), and scanning electron microscopy (SEM) of CSA cement paste were carried out. The XRD analysis confirmed that the main hydration product is ettringite in both freshwater and seawater mixed CSA cement with different w/c ratios. The SEM analysis and physical properties test show that both low w/c ratio and seawater can improve the microstructure of CSA cement. The test results also find out that the high w/c ratio can accelerate the hydration process, extend the setting time, lower the compressive strength, and increase the chemical shrinkage of CSA cement, and the seawater presents a similar influence except for the mechanical property. The seawater increases the compressive strength of CSA cement in the early stage of hydration but will increase the microcracks at the later hydration stage of CSA cement and reduce its mechanical properties.

show abstract

Sulfate diffusion in calcium sulphoaluminate mortar

Cited by 19 publications

References 32 publications

The Damage Performance of Uncarbonated Limestone Cement Pastes Partially Exposed to Na2SO4 Solution

The Damage Performance of Uncarbonated Limestone Cement Pastes Partially Exposed to Na2SO4 Solution

Preparation of Micro-Iron Ore Tailings by Wet-Grinding and Its Application in Sulphoaluminate Cement

Influence of Water‐Cement Ratio and Type of Mixing Water on the Early Hydration Performance of Calcium Sulphoaluminate (CSA) Cement

Contact Info

Product

Resources

About