Carbonation of cement-based materials: Challenges and opportunities

Ashraf, Warda

doi:10.1016/j.conbuildmat.2016.05.080

Cited by 454 publications

(191 citation statements)

References 134 publications

Supporting

Mentioning

172

Contrasting

Unclassified

Order By: Relevance

“…This is a little higher than the previous test results from an accelerated carbonation process [45], and its pH of the semi-carbonated zone is in the range of 9.0 and 11.5. This is most likely due to the higher carbonation rates by using a higher carbon dioxide concentration and controlled environment parameters (i.e., temperature, relative humidity (RH)) of accelerated carbonation on concrete [1]. As a result, the currently used carbonation coefficients of concrete in the evaluation of existing buildings, which are mostly established based on experimental results using an accelerated carbonation process, may be overestimated and not suitable for application to naturally carbonated reinforced concrete structures.…”

Section: The Ph Of Concrete Cover For Corrosion Initiationmentioning

confidence: 92%

See 1 more Smart Citation

Pore Solution pH for the Corrosion Initiation of Rebars Embedded in Concrete under a Long-Term Natural Carbonation Reaction

Liu¹,

Niu²,

Li³

et al. 2018

Applied Sciences

View full text Add to dashboard Cite

Featured Application: The work presented in this paper is suitable for application to the evaluation of existing reinforced concrete structures in buildings, brides, and tunnels.Abstract: This paper presents an in-situ inspection and experimental investigation on the pore solution pH of concrete cover for the corrosion initiation of rebars under a long-term natural carbonation reaction. A 77-year-old steel mill was inspected, and 35 concrete column cover samples were collected to test the pH of the pore solution and phase compositions layer by layer. The variation in pH and phase compositions of the concrete along the cover depth was studied. The in-situ inspection results indicate that the rebar embedded in concrete had begun to corrode when the carbonation depth was almost less than one-third of the cover depth. The corrosion initiation of rebars embedded in concrete can occur when the pH is between 11.3 and 12.1. The pore solution pH test results and X-ray diffraction (XRD) analysis indicated that there is a semi-carbonated zone between the fully carbonated zone and the rebar. The pH of a fully carbonated zone is in a range of 8.0-9.5, and the pH of a semi-carbonated zone is between 9.5 and 12.1.

show abstract

Section: The Ph Of Concrete Cover For Corrosion Initiationmentioning

confidence: 92%

“…Corrosion induced by carbonation is the primary reason for the deterioration of concrete structures exposure to an atmospheric environment [1][2][3][4][5] and non-optimum environments [6][7][8]. The pH of Portland cement concrete is usually in the range of 12.5 to 13.8 [9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Pore Solution pH for the Corrosion Initiation of Rebars Embedded in Concrete under a Long-Term Natural Carbonation Reaction

Liu¹,

Niu²,

Li³

et al. 2018

Applied Sciences

View full text Add to dashboard Cite

show abstract

“…Carbonation curing of concrete has been proposed as a promising route for CO 2 ‐utilization technologies, effectively replacing traditional air curing and steam curing. The technology has two major benefits: (i) rapid strength gain of cementitious materials, and (ii) large‐scale CO 2 sequestration in concrete . In such a process, it allows pressured or concentrated CO 2 gas to penetrate into the concrete, form carbonic acid (H 2 CO 3 ) in the presence of moisture, and finally react with Ca 2+ forming calcium carbonate (CaCO 3 ) …”

Section: Introductionmentioning

confidence: 99%

Carbonation curing of industrial solid waste‐based aerated concretes

et al. 2019

View full text Add to dashboard Cite

Mineral carbonation for concrete curing is a promising route to large‐scale CO2 sequestration and the economic production of building materials. In this work, the carbonation curing of a kind of lightweight concrete, aerated concrete, was comprehensively studied. Three typical industrial wastes – fly ash, blast furnace slag, and red mud – were employed to replace part of the cement and to reduce the carbon footprint of products. The effects of carbonation curing time, pressure, and water‐to‐solids ratio on the CO2 uptake and compressive strength were investigated. Aerated concrete with red mud showed the highest CO2 uptake capacity, followed by concrete with fly ash, and concrete with blast furnace slag. The main crystalline carbonation products, needle‐like calcite and rod‐like aragonite, were observed to be embedded in the surface of fly ash and blast‐furnace‐slag‐based specimens. The orderly structures of carbonated crystals, as well as the reduction of mesoscale porosity (< 50 nm), resulted in an enhancement of mechanical properties. For red‐mud‐based specimens, calcite crystals with the appearance of grains (smaller than 1μm) were formed due to deeper carbonation. The rapid growth of calcite grains may lead to cracks from inside red‐mud‐based specimens and cause a negative effect on mechanical properties. In terms of mechanical performance, the blast furnace slag specimens, after carbonation curing, exhibited the largest compressive strength of 7.3 MPa, which was over 197% higher than that of natural curing for the same duration. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.

show abstract

“…Conventionally, carbonation reaction of concrete is considered unfavorable, as it diminishes the durability of such materials, but for S/S system, this is different [20]. Exposure of S/S-treated waste to carbon dioxide resulted in physical and chemical transformations, which affected the long-term effectiveness of the S/S process.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Carbonation Effects on Cement‐Solidified Contaminated Soil Used in Road Subgrade

Zhou

Pan

Tang

et al. 2018

Advances in Materials Science and Engineering

View full text Add to dashboard Cite

Cement solidification/stabilization is widely used towards contaminated soil since it has a low price and significant improvement for the structural capacity of soil. To increase the usage of the solidified matrix, cement-solidified contaminated soil was used as road subgrade material. In this study, carbonation effect that reflected the durability on strength characteristics of cementsolidified contaminated soil and the settlement of pavement were evaluated through experimental and numerical analysis, respectively. According to results, compressive strengths of specimens with 1% Pb(II) under carbonation and standard curing range from 0.44 MPa to 1.17 MPa and 0.14 MPa to 2.67 MPa, respectively. e relatively low strengths were attributed to immobilization of heavy metal, which consumed part of SiO 2 , Al 2 O 3 , and CaO components in the cement or kaolin and reduced the hydration and pozzolanic reaction materials. is phenomenon further decreased the strength of solidified soils. e carbonation depth of 1% Cu(II) or Zn(II) contaminated soils was 18 mm, which significantly increased with the increase of curing time and contamination concentration. Furthermore, the finite element calculation results showed that surface settlements decreased with the increase of modulus of subgrade and the distance away from the center. At the center, the pavement settlement was proportional to the level of traffic load.

show abstract

Carbonation of cement-based materials: Challenges and opportunities

Cited by 454 publications

References 134 publications

Pore Solution pH for the Corrosion Initiation of Rebars Embedded in Concrete under a Long-Term Natural Carbonation Reaction

Pore Solution pH for the Corrosion Initiation of Rebars Embedded in Concrete under a Long-Term Natural Carbonation Reaction

Carbonation curing of industrial solid waste‐based aerated concretes

Evaluation of Carbonation Effects on Cement‐Solidified Contaminated Soil Used in Road Subgrade

Contact Info

Product

Resources

About