Prediction of Carbonation Depth in Blended Systems

2017 ◽  
pp. 440-446
Author(s):  
V. Shah ◽  
S. Bishnoi
Keyword(s):  
Carbonation Depth

scholarly journals Enhancing carbonation and chloride resistance of autoclaved concrete by incorporating nano-CaCO3

2020 ◽  
Vol 9 (1) ◽  
pp. 998-1008
Author(s):  
Guo Li ◽  
Zheng Zhuang ◽  
Yajun Lv ◽  
Kejin Wang ◽  
David Hui
Keyword(s):  
Cement Hydration ◽  
Mercury Intrusion Porosimetry ◽  
Hardened Concrete ◽  
Optimal Dosage ◽  
Hydration Products ◽  
X Ray Diffraction ◽  
Carbonation Depth ◽  
X Ray ◽  
Chloride Resistance

AbstractThree nano-CaCO3 (NC) replacement levels of 1, 2, and 3% (by weight of cement) were utilized in autoclaved concrete. The accelerated carbonation depth and Coulomb electric fluxes of the hardened concrete were tested periodically at the ages of 28, 90, 180, and 300 days. In addition, X-ray diffraction, thermogravimetry, and mercury intrusion porosimetry were also performed to study changes in the hydration products of cement and microscopic pore structure of concrete under autoclave curing. Results indicated that a suitable level of NC replacement exerts filling and accelerating effects, promotes the generation of cement hydration products, reduces porosity, and refines the micropores of autoclaved concrete. These effects substantially enhanced the carbonation and chloride resistance of the autoclaved concrete and endowed the material with resistances approaching or exceeding that of standard cured concrete. Among the three NC replacement ratios, the 3% NC replacement was the optimal dosage for improving the long-term carbonation and chloride resistance of concrete.

scholarly journals Carbonization Durability of Two Generations of Recycled Coarse Aggregate Concrete with Effect of Chloride Ion Corrosion

2020 ◽  
Vol 12 (24) ◽  
pp. 10544
Author(s):  
Chunhong Chen ◽  
Ronggui Liu ◽  
Pinghua Zhu ◽  
Hui Liu ◽  
Xinjie Wang
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Chloride Ion ◽  
Total Porosity ◽  
Recycled Concrete ◽  
Carbonation Depth ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Carbonation Resistance ◽  
Two Generations

Carbonation durability is an important subject for recycled coarse aggregate concrete (RAC) applied to structural concrete. Extensive studies were carried out on the carbonation resistance of RAC under general environmental conditions, but limited researches investigated carbonation resistance when exposed to chloride ion corrosion, which is an essential aspect for reinforced concrete materials to be adopted in real-world applications. This paper presents a study on the carbonation durability of two generations of 100% RAC with the effect of chloride ion corrosion. The quality evolution of recycled concrete coarse aggregate (RCA) with the increasing recycling cycles was analyzed, and carbonation depth, compressive strength and the porosity of RAC were measured before and after chloride ion corrosion. The results show that the effect of chloride ion corrosion negatively affected the carbonation resistance of RAC, and the negative effect was more severe with the increasing recycling cycles of RCA. Chloride ion corrosion led to a decrease in compressive strength, while an increase in carbonation depth and the porosity of RAC. The equation of concrete total porosity and carbonation depth was established, which could effectively judge the deterioration of carbonation resistance of RAC.

scholarly journals Carbonation Resistance of Surface Protective Materials Modified with Hybrid NanoSiO2

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 269
Author(s):  
Kailun Xia ◽  
Yue Gu ◽  
Linhua Jiang ◽  
Mingzhi Guo ◽  
Lei Chen ◽  
...  
Keyword(s):  
Construction Material ◽  
Chemical Components ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Carbonation Depth ◽  
X Ray ◽  
Carbonation Resistance ◽  
Ideal Situation ◽  
Caco3 Content ◽  
Reference Samples

To date, reinforcement concrete is the main construction material worldwide. As the concentration of atmospheric CO2 is steadily increasing, carbonation of the reinforcement concrete becomes a pressing concern. In this study, novel surface protective materials (SPMs) modified with hybrid nanoSiO2 (HNS), fly ash, and slag were developed to reduce CO2 emissions and extend the service life of the reinforcement concrete. The carbonation depths were measured by phenolphthalein to reflect the carbonation resistance. X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FTIR), and thermal gravimetric analysis (TGA) were conducted to analyze the chemical components of the samples after carbonation. In addition, MIP was carried out to examine the microstructures of the samples prior to carbonation. Thermodynamic modeling was employed to calculate the changes in the phase assemblages of each blends in an ideal situation. The experimental results showed that the carbonation depth and CaCO3 content of the SPM modified with HNS decreased by 79.0% and 64.6% compared with the reference, respectively. The TGA results showed that after carbonation, the CaCO3 contents were 4.40% and 12.42% in the HNS modified samples and reference samples, respectively. MIP analysis demonstrated that the incorporation of HNS in SPM led to a 48.3% and 58.5% decrease in big pores and capillary pores, respectively. Overall, the SPMs modified with HNS in this study possessed better carbonation resistance and refined pore structures.

scholarly journals Effects of Environmental Factors on Concrete Carbonation Depth and Compressive Strength

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2167 ◽  
Author(s):  
Ying Chen ◽  
Peng Liu ◽  
Zhiwu Yu
Keyword(s):  
Compressive Strength ◽  
Phase Composition ◽  
Relative Humidity ◽  
Co2 Concentration ◽  
Crystal Structure Analysis ◽  
Hydration Products ◽  
Carbonation Depth ◽  
Concrete Carbonation ◽  
Before And After ◽  
Compressive Strength Of Concrete

The influence of temperature, CO2 concentration and relative humidity on the carbonation depth and compressive strength of concrete was investigated. Meanwhile, phase composition, types of hydration products and microstructure characteristics of samples before and after the carbonation were analyzed by XRD and ESEM. Research results demonstrate that temperature, CO2 concentration and relative humidity influence the carbonation depth and compressive strength of concrete significantly. There is a linear relationship between temperature and carbonation depth, as well as the compressive strength of concrete. CO2 concentration and relative humidity present a power function and a polynomial function with carbonation depth of concrete, respectively. The concrete carbonation depth increases with the increase of relative humidity and reaches the maximum value when the relative humidity is 70%. Significant differences of phase composition, hydration products and microstructure are observed before and after the carbonation. Carbonization products of samples are different with changes of temperatures (10 °C, 20 °C and 30 °C). The result of crystal structure analysis indicates that the carbonation products are mainly polyhedral spherical vaterite and aragonite.

scholarly journals Effect of Graphene Nanoplatelet on the Carbonation Depth of Concrete under Changing Climate Conditions

2021 ◽  
Vol 11 (19) ◽  
pp. 9265
Author(s):  
Yingzi Zhang ◽  
Yanze Wang ◽  
Mingqian Yang ◽  
Huatao Wang ◽  
Guofang Chen ◽  
...  
Keyword(s):  
Control Sample ◽  
Co2 Concentration ◽  
Favorable Effect ◽  
Carbonation Depth ◽  
Graphene Nanoplatelet ◽  
Carbonation Reaction ◽  
Climate Conditions ◽  
Ordinary Concrete ◽  
Changing Climate ◽  
Carbon Dioxide Co2

Climate change has been unprecedented in the past decades or even thousands of years, which has had an adverse impact on the mechanical properties of concrete structures. Many researchers have begun to study new concrete materials. Graphene nanoplatelet (GNP) is an attractive nanomaterial that can change the crystal structure of concrete and improve durability. The aim of the present study was to investigate the effect of GNP (0.05%wt) on the carbonation depth of concrete under simulated changing climate conditions (varying temperature, relative humidity, and carbon dioxide (CO2) concentration), and compare it with ordinary concrete. When the concentration of CO2 is variable, the carbonation depth of graphene concrete is 10% to 20% lower than that of ordinary concrete. When the temperature is lower than 33 °C, the carbonation depth of graphene concrete is less than that of the control sample; however, above 33 °C, the thermal conductivity of GNP increases the carbonation reaction rate of concrete. When the humidity is a variable, the carbonation depth of graphene concrete is less than 15% to 30% of ordinary concrete, and when the humidity is higher than 78%, the difference in the carbonation depth between the ordinary concrete and the graphene concrete decreases gradually. The overall results indicated that GNP has a favorable effect on anti-carbonation performance under changing climate conditions.

scholarly journals Effect of Soorh Metakaolin on Concrete Compressive Strength and Durability

2017 ◽  
Vol 7 (6) ◽  
pp. 2210-2214 ◽  
Author(s):  
A. Saand ◽  
M. A. Keerio ◽  
D. K. Bangwar
Keyword(s):  
Compressive Strength ◽  
Corrosion Resistance ◽  
Life Time ◽  
Natural Material ◽  
Concrete Durability ◽  
Concrete Compressive Strength ◽  
Water Penetration ◽  
Carbonation Depth ◽  
Ordinary Concrete ◽  
Strength And Durability

Concrete durability is a key aspect for forecasting the expected life time of concrete structures. In this paper, the effect of compressive strength and durability of concrete containing metakaolin developed from a local natural material (Soorh of Thatta Distict of Sindh, Pakistan) is investigated. Soorh is calcined by an electric furnace at 8000C for 2 hours to produce metakaolin. One mix of ordinary concrete and five mixes of metakaolin concrete were prepared, where cement is replaced by developed metakaolin from 5% to 25% by weight, with 5% increment step. The concrete durability was tested for water penetration, carbonation depth and corrosion resistance. The obtained outcomes demonstrated that, 15% replacement level of local developed metakaolin presents considerable improvements in concrete properties. Moreover, a considerable linear relationship was established between compressive strength and concrete durability indicators like water penetration, carbonation depth and corrosion resistance.

scholarly journals Identification and analysis of pathological defect appearance in superstructures of reinforced-concrete bridges in Chapare region, Bolivia

DYNA ◽  
2021 ◽  
Vol 88 (216) ◽  
pp. 15-21
Author(s):  
Joaquin Humberto Aquino Rocha ◽  
Rolando Ibarra Villanueva
Keyword(s):  
Visual Inspection ◽  
Structural Characteristics ◽  
Concrete Bridges ◽  
High Humidity ◽  
Carbonation Depth ◽  
Carbonation Process ◽  
Reinforced Concrete Bridges ◽  
Inspection And Maintenance ◽  
Core Extraction ◽  
Selection Of

The objective of this article is to identify and analyze the main pathological manifestations in bridges in the Chapare - Bolivia region, an area characterized by high humidity and constant rainfall throughout the year. The methodology consisted of the selection of five bridges that showed evident signs of deterioration, in which a visual inspection was carried out and, subsequently, different tests: sclerometer, carbonation depth, penetration of chlorides and core extraction. All the bridges present advanced states of deterioration; highlighting corrosion as the main problem, generating detachment of the concrete and risk of collapse. Although the concrete has a compression strength greater than 30 MPa, the existing carbonation process and the different problems encountered compromises it. It is necessary that the entities in charge provide inspection and maintenance programs according to the environmental and structural characteristics of each bridge.

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