Deterioration mechanism of CA mortar due to simulated acid rain

Zeng, Xiaohui; Li, Yirui; Ran, Yuzhou; Yang, Kai; Qu, Fulin; Wang, Ping

doi:10.1016/j.conbuildmat.2018.03.033

Cited by 39 publications

(12 citation statements)

References 21 publications

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“…However, EACSH is characterized by spherical particles whose diameter was about 5 μm, as shown in Figure 9, the particle size of asphalt in asphalt emulsion was about 2 μm, and the asphalt particle may be an important role for the change of microstructure of CSH. It is known that emulsifiers exist on the surface of asphalt particles, 3–7 and the emulsifier may adsorb CSH gels result in globular accumulation state. Differences in the mesopore structure of gel samples (Figure 5) were also due to changes in the build‐up state of the CSH gels.…”

Section: Microstructure Characterisesmentioning

confidence: 99%

“…Cement and asphalt emulsion (CA) mortar, which serves as a key functional material in high‐speed railways, is composed of cement, asphalt emulsion, sand and various admixtures 1–3 . There are two types of CA mortar: the type‐I structure, with asphalt as the continuous phase and cement as the dispersed phase, and the type‐II structure, with cement as the matrix and asphalt embedded therein 4 .…”

Section: Introductionmentioning

confidence: 99%

“…Based on the above similar CSH nanostructure, some studies 11 used molecular dynamics to calculate the mechanical properties of CSH/PEG (polyethylene glycol), CSH/PAA (acrylic acid polymers) and CSH/PVA (polyvinyl alcohol), which strongly affects the tensile strength in the z direction in the calcium silicate lattice. CA mortar, reported as an organic–inorganic composite material composed of particles of various scales, had a complex microstructure and need more in‐depth researches 1,3,12–14 Thus, it is important to study the effect of asphalt emulsion on texture and porosity of CSH.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of asphalt emulsion on calcium silicate hydrate gel: Morphology and porosity

Zeng

Zhu

Lan

et al. 2020

Asia-Pacific J Chem Eng

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In this paper, calcium silicate hydrate (CSH) gel and calcium silicate hydrate doped with asphalt emulsion (EACSH) were synthesised using Na2SiO3•9H2O, Ca (NO3)2•4H2O, NaOH, deionised water and anionic asphalt emulsion. N2 isothermal adsorption, X‐ray diffraction (XRD) and scanning electron microscopy (SEM) were used to study the effect of asphalt emulsion on morphology and porosity of CSH. The Frenkel–Halsey–Hill (FHH) model was used to analyse the surface fractal characteristics. The results showed that the asphalt emulsion had little effects on the change of specific surface areas and the distribution of the micropores for CSH gel, which may be related to the absence of the intercalation reaction and the “opening” effect. The asphalt emulsion could promote the formation of mesoporous hydrated calcium silicate and decreased the number of mesopores in CSH gel but had little effects on the macroporous and microporous structure of CSH. The calculation results of the FHH model showed that the fractal characteristics between CSH and EACSH were different. The emulsifier may adsorb CSH gels result in globular accumulation state.

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Section: Microstructure Characterisesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of asphalt emulsion on calcium silicate hydrate gel: Morphology and porosity

Zeng

Zhu

Lan

et al. 2020

Asia-Pacific J Chem Eng

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“…It was found by Zhu and Cai [6] that the temperature difference between the top and bottom surfaces of track slab can reach over 16 • C. The temperature gradient load induced by the great temperature differential may result in the generation of pulling and curling stresses in the prefabricated concrete slabs [32] and structural defects. Typical temperature-induced slab track defects include interface debonding/delamination between CA mortar and track slab [4,7,12,18,25,26,32,39], decreased compressive strength, cracking and damage of CA mortar [9,15,16,33,35,[40][41][42], wide and narrow juncture defects [8], warping deformation of track slab [13,16,26,38], etc.…”

Section: Temperature-induced Slab Defects and Warping Deformationmentioning

confidence: 99%

Identification of Temperature-Induced Deformation for HSR Slab Track Using Track Geometry Measurement Data

Liu

2019

Sensors

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Slab track is widely used in many newly built high-speed rail (HSR) lines as it offers many advantages over ballasted tracks. However, in actual operation, slab tracks are subjected to operational and environmental factors, and structural damages are frequently reported. One of the most critical problems is temperature-induced slab-warping deformation (SWD) which can jeopardize the safety of train operation. This paper proposes an automatic slab deformation detection method in light of the track geometry measurement data, which are collected by high-speed track geometry car (HSTGC). The characteristic of track vertical irregularity is first analyzed in both time and frequency domain, and the feature of slab-warping phenomenon is observed. To quantify the severity of SWD, a slab-warping index (SWI) is established based on warping-sensitive feature extraction using discrete wavelet transform (DWT). The performance of the proposed algorithm is verified against visual inspection recorded on four sections of China HSR line, which are constructed with the China Railway Track System II (CRTSII) slab track. The results show that among the 24,806 slabs being assessed, over 94% of the slabs with warping deformation can be successfully identified by the proposed detection method. This study is expected to provide guidance for efficiently detecting and locating slab track defects, taking advantage of the massive track inspection data.

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“…Simulated acid rainfall contained sulphuric acid and nitric acid with a ratio of 2:1 using the volume-concentration formula, which was simulated at three pH levels: 3.75, 4.25, and 5.25. These levels were selected because they are to the most representative ranges found in several recent studies with negative effects in agricultural or natural fields and buildings (Du et al, 2017;Livingston, 2016;Mahdikhani, Bamshad, & Fallah Shirvani, 2018;Zeng et al, 2018). Moreover, rainfall simulations with non-acidic rain (pH = 7.5) were also conducted in order to compare acid rain with a control situation.…”

Section: Rainfall Simulator Characteristicsmentioning

confidence: 99%

The increase of rainfall erosivity and initial soil erosion processes due to rainfall acidification

Kavian

Alipour

Soleimani

et al. 2018

Hydrological Processes

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The drastic growth of population in highly industrialized urban areas, as well as fossil fuel use, is increasing levels of airborne pollutants and enhancing acid rain. In rapidly developing countries such as Iran, the occurrence of acid rain has also increased. Acid rain is a driving factor of erosion due to the destructive effects on biota and aggregate stability; however, little is known about its impact on specific rates of erosion at the pedon scale. Thus, the present study aimed to investigate the effect of acid rain at pH levels of 5.25, 4.25, and 3.75 for rainfall intensities of 40, 60, and 80 mm h−1 on initial soil erosion processes under dry and saturated soil conditions using rainfall simulations. The results were compared using a two‐way ANOVA and Duncan tests and showed that initial soil erosion rates with acidic rain and non‐acidic rain under dry soil conditions were significantly different. The highest levels of soil particle loss due to splash effects in all rainfall intensities were observed with the most acidic rain (pH = 3.75), reaching maximum values of 16 g m−2 min−1. The lowest levels of particle losses were observed in the control plot where non‐acidic rain was used, with values ranging from 3.8 to 8.1 g m−2 min−1. Similarly, under saturated soil conditions, the lowest level of soil particle loss was observed in the control plot, and the highest peaks of soil loss were observed for the most acidic rains (pH = 3.75 and pH = 4.25), reaching maximum average values of 40 g m−2 min−1. However, for saturated soils with acidic water but with non‐acidic rain, the highest soil particle loss was observed for the control plot for all the rainfall intensities. In conclusion, acidic rain has a negative impact on soils, which can be more intense with a concomitant increase in rainfall intensity. Rapid solutions, therefore, need to be found to reduce the emission of pollutants into the air, otherwise, rainfall erosivity may drastically increase.

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Deterioration mechanism of CA mortar due to simulated acid rain

Cited by 39 publications

References 21 publications

Effects of asphalt emulsion on calcium silicate hydrate gel: Morphology and porosity

Effects of asphalt emulsion on calcium silicate hydrate gel: Morphology and porosity

Identification of Temperature-Induced Deformation for HSR Slab Track Using Track Geometry Measurement Data

The increase of rainfall erosivity and initial soil erosion processes due to rainfall acidification

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