Carbonation Resistance Research Articles

Recent Advances in Properties and Application Progress of Cement-Based Materials with Iron Tailing

In the context of the comprehensive green transformation of infrastructure construction, utilizing bulk waste tailings materials, such as iron tailing, in cement-based materials commonly used in the infrastructure sector holds significant practical importance. However, there are differences in the range of iron tailings content used in previous studies, and the research results are quite scattered. There has not yet been a recommendation for a reasonable material ratio, which severely restricts the resource utilization of iron tailings in cement-based materials. To effectively guide the design and performance optimization of cement-based materials using iron tailing, recent advances related to iron tailing cement-based materials have been reviewed systematically. The previous studies on the composition design of iron tailing in cement-based materials were summarized, and the effect of iron tailing and cement on the mechanical properties and durability of various cement-based materials were highlighted. The results show that the recommended content of iron tailing sand in concrete is 25–50%. Under this content, the mechanical properties of iron tailing sand concrete increase the most, and it has better drying shrinkage performance and carbonation resistance. For cement stabilized base materials, the recommended content of iron tailing sand is 11–20%. Under this content, its mechanical properties increase significantly, and it also has excellent drying shrinkage and temperature shrinkage performance. The increase in the content of iron tailing stones reduces the mechanical properties of cement stabilized materials. Cement stabilized iron tailing stones can be applied to the roadbase by adjusting the cement content and the content of iron tailing stones.

Bifunctional carbon elimination mechanism of CeO2 nanorod@Ni3Co7Phy core shell catalyst for CO2 reforming of methane

CO2 capture and utilization via reforming of methane (DRM) is an efficient route to promote the achievement of the carbon neutralization goal. Whereas, the carbon deposition problem on cheap Ni-based catalysts slows down its industrial progress. Although Co doping to form NiCo bimetallic catalysts is effective to enhance the carbon resistance, the bifunctional carbon elimination mechanism has not been unveiled. Here, core shell structured CeO2@Ni7Co3Phy catalyst with high sintering and carbon resistance has been designed, exhibiting the stable CH4 and CO2 conversion of 72 % and 78 % respectively at 973 K for 120 h. The outstanding performance is due to the formation of Ni7Co3 bimetal, enhanced metal support interaction, and the highest surface Ni0 concentration, increasing sintering resistance and boosting the DRM activity. In situ diffuse infrared Fourier transform spectroscopy analysis and density functional theory calculations further confirm the bifunctional carbon elimination mechanism that both the oxygen vacancies in CeO2 and the electron deficient oxidative Co sites adsorb and activate CO2, providing oxygen species to eliminate carbon. By comparison, either serious Ni sintering and carbon accumulation or oxidation of Co0 phase due to excessive CO2 activation occurred for CeO2@NiPhy and CeO2@CoPhy catalyst respectively, leading to their worse DRM performance. The bifunctional carbon elimination mechanism illuminates the design of other carbon resistant catalysts.

Effects of CaO-based expansive agent on carbonation resistance of marine concrete

Marine concrete contains a high volume of supplementary cementitious materials, which benefits low-carbon concrete production. However, they may also increase the risk of cracking and accelerate the carbonation due to the pozzolanic reaction. Theoretically, the CaO-based expansive agent (CEA) can inhibit shrinkage cracks and introduce external calcium sources that aid in the carbonation resistance of concrete. A comprehensive understanding of the impact of CEA on the carbonation resistance of marine concrete is currently scarce.In this study, marine concretes with varying dosages of CEA were exposed to 20% CO2 for 28 days. The carbonation depth, carbonation coefficient, air permeability, pore structure characteristics and CO2 buffer capacity of concrete were investigated. When the CEA dosage was less than 6%, the carbonation resistance and air permeability approached the reference groups in normal-strength concrete (NSC) and high-strength concrete (HSC). However, more than 6% CEA significantly decreased the carbonation resistance of concrete, particularly for HSC. For NSC, there was an excellent correlation between the carbonation coefficient and compressive strength, while for HSC, the carbonation coefficient correlated well with porosity. Also, CO2 buffer capacity was essential to assess the carbonation resistance of marine concrete.

Carbonation resistance of recycled sand concrete and its splitting tensile strength after carbonation

Carbonation resistance of recycled sand concrete and its splitting tensile strength after carbonation

Improving carbonation resistance, strength, and microstructure of concrete through compression casting

Improving carbonation resistance, strength, and microstructure of concrete through compression casting

Corrosion and carbonation resistance of mortars incorporating rice husk ash

The Rice Husk Ash (RHA) was obtained by incinerating Rice Husk with a temperature of 300℃, 500℃, 700℃, and then added into control mortars as replacement of cement to prepare modified mortars. The microstructure of RHA was characterized by FT-IR test, then the corrosion and carbonation resistance of mortars were investigated. Additionally, the microstructure of cement mortars was revealed using the SEM test. Researched results indicated that the cement hydration is improved and the mezzanine structure of RHA at 700℃ is compact, while the mezzanine of RHA at 300℃ is composed of crisscross plates. Moreover, the incorporation of RHA improves the corrosion and carbonation resistance of mortars.

Effect of carbonation on the properties of self-healing concrete with expanded perlite as a microbial carrier

Expanded perlite (EP) is a microbial carrier used in microbial self-healing concrete (MSHC). However, the type of EP microbial self-healing agent (EPMSA) affects MSHC performance, especially with coupled carbonation and microbial-induced calcite precipitation (MICP). In this study, two EPMSAs were prepared (one coated and one uncoated by magnesium potassium phosphate cement (MKPC)) and two MSHC specimens were developed. The effects of carbonation on the carbonation depth, compressive strength, chloride penetration, and crack self-healing properties of MSHC were investigated. The results showed that the MSHC prepared with uncoated EPMSA had merely 1–2.2 mm carbonation depth and 63.8 MPa compressive strength after 28 days of carbonation. The uncoated EPMSA in MSHC induced more calcium carbonate than the coated EPMSA, thus improving the pore structure of MSHC, which is why MSHC exhibits high carbonation resistance and compressive strength. Although carbonation reduced the crack self-healing performance, the maximum healed crack width of MSHC incorporated with uncoated EPMSA could still reach 0.81 mm. Due to the positive effect of EP, MHSC has excellent resistance to chloride penetration. The dual action of EP and MICP makes uncoated EPMSA-incorporated MHSC exhibit excellent durability attributes. Using uncoated EPMSA is a more prudent approach when the strength and durability of MSHC are of critical concern.

Study on activation and performance of recycled hardened concrete powder based on microbial accelerated carbonization

Recycled hardened concrete powder (RHCP) was used as a raw material, and microorganisms were introduced to accelerate carbonization to enhance its activity. The carbonation ability of RHCP was investigated by altering the solid-liquid ratio during carbonation. The results indicated that the carbon sequestration amount of RHCP after 7 days of carbonation at room temperature and pressure initially increased and then decreased with the rise of the solid-liquid ratio. When the solid-liquid ratio was 1:0.8, the carbon sequestration amount of RHCP was the highest, reaching 208.65 g/kg. The carbonized RHCP (C-RHCP) and RHCP were then used to partially replace cement to investigate their effects on the workability, mechanical, and durability properties of the mixtures. The results showed that when the replacement amount of C-RHCP was 30 %, all the properties were relatively good. The water demand and setting time were not significantly different. After 28 days of curing, the compressive strength of the 30 % C-RHCP specimen reached over 70 % of that of the pure cement group. However, its carbonation resistance was significantly lower than that of pure cement, while its resistance to chloride ion penetration and drying shrinkage was similar.

A Critical Review of the Technical Characteristics of Recycled Brick Powder and Its Influence on Concrete Properties

This paper presents a systematic overview of the applications of RBP as a substitute for cement. Initially, the fundamental properties of RBP, including physical properties, chemical compositions, and morphology, are discussed. Subsequently, the effects of RBP on various aspects of cement-based materials, such as fresh properties, shrinkage behavior, hydration, microstructure, strength development, and durability, are thoroughly reviewed. The findings of this study reveal that waste brick powder exhibits pozzolanic activity and can be used to partially replace cement in concrete formulations. However, its relatively high water absorption and irregular shape increase the water demand and, thus, reduce the rheological properties. The incorporation of RBP with 10–20% or finer particle sizes can refine the pore structure and promote the formation of hydration products. However, replacements of RBP greater than 25% can lead to adverse effects on the mechanical properties, frost resistance, and carbonation resistance of cementitious composites. Therefore, to enhance the effectiveness of RBP, measures such as improving fineness, incorporating mineral admixtures, adjusting curing conditions, and applying nano- or chemical modifications are necessary. This study provides valuable technical support for promoting the sustainable preparation of construction materials, which holds important environmental and economic implications.

Preparation of ester-modified nano-SiO2/silicate coatings and its application in the impermeability of concrete

Surface treatment protective technology is a cost-effective approach to prevent harmful ions from infiltrating concrete, avoiding the deterioration of performance and increasing longevity. Here, a novel coupling agent with ester group (MA-KH-550) is synthesized from γ-aminopropyltriethoxysilane (KH-550) and methyl acrylate (MA) to modify nano-SiO2 particles. Subsequently, the ester-modified nano-SiO2 can be successfully dispersed in alkaline composite silicate solutions to fabricate nano-SiO2/silicate coatings, improving the impermeability of concrete. The incorporation of nano-SiO2 particles can fill microscopic pores in cementitious materials, which improves the compactness of the concrete. Furthermore, nano-SiO2 particles can also accelerate secondary hydration of cement and synergistically generate more calcium silicate hydrate gel with silicates to further boost the compactness of the concrete. High-compactness coatings reduce the penetration of the medium, thereby enhancing the impermeability performance of the concrete. When the nano-SiO2 particle content is 1.0 wt%, the optimal performance of concrete is achieved. Compared with the original C30 concrete, the C30 concrete treated with the nano-SiO2/composite silicate (nano-SiO2/CSC) shows a 31.1 % decrease in chloride ion resistance, a 35.5 % reduction in carbonization resistance, a loss rate of 1.08 % for anti-freezing quality. This work charts a new course for designing and developing high-performance composite silicate coatings for concrete.

Durability of Steel-Reinforced Concrete Structures Under Effect of Climatic Temporality and Aggressive Agents (CO2, SO2) in Boca del Rio, Veracruz

The development of sustainable infrastructure is essential to address the challenges of climate change and reduce CO2 emissions. The use of alternative materials, such as agro-industrial ashes and silica fume, emerges as a promising option to enhance the durability of concrete and diminish its environmental impact. These materials can partially replace conventional cement, contributing to the construction of more sustainable infrastructure without compromising performance, even under adverse environmental conditions. In this study, we present an analysis of the use of sugarcane bagasse ash (SBA) and silica fume (SF) as a 15% cement replacement. The behavior of these materials was investigated under coastal conditions, analyzing climatic variables and degrading gases such as CO2, CH4, and N2O. Electrochemical techniques were employed to measure corrosion rate and potential, in addition to conducting carbonation and compressive strength tests. The mixtures with a 15% addition of SBA and SF showed improvements compared to conventional mixes. SBA reduced the corrosion rate by 25% and increased compressive strength by 12% after 150 days, while SF enhanced carbonation resistance by 20% and compressive strength by 25%. The incorporation of SBA and SF provides significant durability in coastal environments, contributing to the sustainability of infrastructure exposed to adverse weather conditions.

Thermodynamic study on the phase assemblage of MPC exposed to natural and accelerated carbonation conditions

AbstractMagnesium phosphate cement (MPC), which belongs to chemically bonded phosphate ceramics, is commonly applied as a repair material and waste stabilization/solidifications. However, studies on the influence of CO2 on the phase assemblages in MPC are limited. A thermodynamic simulation approach is employed to explore the influence of CO2 on the equilibrium phase assemblage of MPC. The mechanisms of natural and enforced carbonation of MPC have been investigated in this work. The results disclose that Mg carbonates are less likely to precipitate in magnesium ammonium phosphate cement (MAPC) cured under CO2, while MgCO3·3H2O is the only carbonation product of magnesium potassium phosphate cement (MKPC). The carbonation resistance of MAPC is better than that of MKPC. The increase of activity of magnesia employed in MPC obviously enhances the formation of brucite and slightly promotes the carbonation of MPC.

Enhancing carbonation resistance of low-activity coal gangue-based LC3 cementitious materials with Ca(OH)₂ and gypsum additives

The utilization of coal gangue in limestone calcined clay cement (LC3) has been limited by its relatively low activity and poor carbonation resistance. This research evaluates the effects of adding Ca(OH)2 and gypsum to enhance the carbonation resistance and mechanical properties of coal gangue-based LC3. Coal gangue-based LC3 with 60 % coal gangue replacement exhibits limited carbonation resistance, with a carbonation depth of 19.3 mm and a post-carbonation compressive strength of 20.4 MPa. However, with the incorporation of 7.15 % Ca(OH)2 and 10 % gypsum, the carbonation depth reduces to 17.0 mm and the compressive strength increases to 31.9 MPa. In the composite with 30 % coal gangue, the addition of 20 % gypsum results in a carbonation depth of 10 mm and a compressive strength of 39.3 MPa. These findings provide crucial insights for the optimization and industrial application of sustainable cement materials.

Carbonization test and orthogonal polynomial regression analysis of steel fiber reclaimed concrete

To enhance the carbonation resistance of reclaimed concrete, several key factors affecting its performance were investigated. An orthogonal array L16(4³×2⁶) was employed to design the carbonation tests for steel fiber (SF) reinforced concrete. The study included varying SF volume ratios, along with considerations of different concrete ages (T) and water-cement ratios (W/R). The effect of SF volume ratio, regenerated crude aggregate (RCA) replacement rate, W/R, and T on the carbonation resistance of recycled concrete was analyzed. The test results indicated a trend of increasing carbonation depth over time. However, a lower W/R ratio resulted in a reduced carbonation depth. Notably, a 50% RCA replacement rate led to a shallower carbonation depth compared to other replacement rates. After 28 d, recycled concrete containing 1% SF exhibited a carbonation depth that was 6.9%, 1.5%, 1.5%, and 9.3% lower than concrete with 0%, 0.5%, 1.5%, and 2% SF, respectively. Therefore, the incorporation of 1% SF was found to be the most effective in improving carbonation resistance. Orthogonal polynomial regression analysis was employed to develop a regression equation relating carbonation depth to SF volume ratio, RCA replacement rate, W/R, and T. The regression coefficients were calculated and tested, leading to the identification of the optimal regression equation and its corresponding confidence interval.

Utilizing incineration bottom ash-infused steel fiber-reinforced concrete: An analysis of compressive strength and carbonation durability

This study has developed concrete with moderate strength, and excellent carbonation resistance, by blending incineration bottom ash with steel fibers into the concrete mixture. Through single-factor experiments, investigate the effects of bottom ash content and steel fiber volume fraction on the mechanical properties and carbonation resistance of concrete. The results indicate that the addition of steel fibers effectively reduces the adverse effects of incineration bottom ash content on the compressive strength and carbonation level of concrete. When the bottom ash content is 20 % and the steel fiber content is 2 %, the compressive strength of concrete reaches 56.1 MPa, and the carbonation depth drops to 4.19 mm after 28 days. In addition, a carbonation depth prediction model was established based on the compressive performance of concrete, accurately predicting the carbonation depth at different carbonation stages.

Hydrogen enriched natural gas-fueled solid oxide fuel cells supported by Ni-Cu co-doping CeO2-δ catalyst-modified finger-like pore anode

Hydrogen blending in natural gas pipelines is one of the key technologies to realize the long-distance hydrogen transmission, which facilitates the large-scale hydrogen utilization. Solid oxide fuel cells can directly use hydrogen enriched natural gas (HENG, with 20 % H2) to generate electricity without separating and purifying the hydrogen, which enables the efficient conversion of hydrogen energy. In this work, finger-like pore anodes and Ni0.05Cu0.05Ce0.9O2-δ (NCCO) catalyst are prepared to address the need for anode performance and stability with hydrogen-doped natural gas fuels. The results show that NiCu@CeO2 precipitates NiCu nano-alloys on the surface after reduction treatment, which is beneficial for the anode activity. With NCCO catalyst, the maximum power densities of the single cells are 970 mW cm−2 and 700 mW cm−2 at 750 °C under wet H2 and HENG fuel atmospheres, respectively. At 750 °C, the methane conversion is as high as 46 %. More importantly, the single cell can run smoothly for 150 h, with the constant voltage (0.8 V) discharge and HENG as fuel gas. Our results confirm that the synthesized NCCO catalysts have excellent ability to catalyze CH4 and carbon resistance.

Effect of Different Tempering Media on Fracture Toughness and Mechanical Properties of Carbon Steel

In this study, the effect of different thermal carbons on the impact resistance of heavy carbon, which contains 0.4% of. The focus was on how the resulting biochemistry affects the microstructure of the steel, and thus its mechanical properties. Steps: Impact test before heat treatment: Charpy impact test was performed on pre- impact specimens before any specimen was made. This test helps to determine the original impact of the steel without any modification in its microstructure. Tempering procedure: After that, it was further investigated by exposing it to high temperatures and then cooling it rapidly. This method is for market formation, which is a must. It was retested after tempering. The results showed a significant increase in the shock cases after tempering due to the formation of the texture which increased the strength of the specimen. Flame tempering (surface heat treatment): In this type of treatment, only the surface is heated with a flame and cooled rapidly, which results in the formation of a strong martensite texture on the surface, while the core of the specimen remains softer. When tested, it did get shock, but the amount of increase that occurred with full shock was not reduced. The reason for this is that the hardening in God is only on the surface while the core of the eye remains flexible, which leads to a reduction in contrast. Carburizing (surface heat treatment): Carburizing treatment is performed on some samples, which is a method that involves adding carbon to the outer surface of the fulminate and cooling it rapidly, resulting in a solid, hard material. When performing the shock test, it did get a shock that improved, but a case like flame hardening, you did not have very many shocks in full hardening.

Productive Poplar Genotypes Exhibited Temporally Stable Low Stem Embolism Resistance and Hydraulic Resistance Segmentation at the Stem-Leaf Transition.

Breeding tree genotypes that are both productive and drought-resistant is a primary goal in forestry. However, the relationships between plant hydraulics and yield at the genotype level, and their temporal stabilities, remain unclear. We selected six poplar genotypes from I-101 (Populus alba) × 84 K (P. alba × Popolus tremula var. glandulosa) for experiments in the first and fourth years after planting in a common garden. Measurements included stem embolism resistance, shoot hydraulic resistance and its partitioning between stems and leaves, vessel- and pit-level anatomy, leaf carbon acquisition capacity, carbon allocation to leaves, and aboveground biomass (yield proxy). Significant genetic variations in hydraulic properties and yield were found among genotypes in both years. Productive genotypes had wide vessels, large thin pit membranes, small pit apertures, and shallow pit chambers. Hydraulic resistance was negatively correlated with yield, enabling high stomatal conductance and assimilation rates. Productive genotypes allocated less aboveground carbon and hydraulic resistance to leaves. Temporally stable trade-offs between stem embolism resistance and yield, and between hydraulic segmentation and yield, were identified. These findings highlight the tight link between hydraulic function and yield and suggest that stable trade-offs may challenge breeding poplar genotypes that are both productive and drought-resistant.

The Influence and Mechanism of Polyvinyl Alcohol Fiber on the Mechanical Properties and Durability of High-Performance Shotcrete

This study investigates the impact of polyvinyl alcohol (PVA) fibers on the mechanical properties and durability of high-performance shotcrete (HPS). Results demonstrate that PVA fibers have a dual impact on the performance of HPS. Positively, PVA fibers enhance the tensile strength and toughness of shotcrete due to their intrinsic high tensile strength and fiber-bridging effect, which significantly improves the material’s splitting tensile strength, deformation resistance, and toughness, and the splitting tensile strength and peak strain have been found to be increased by up to 30.77% and 31.51%, respectively. On the other hand, the random distribution and potential agglomeration of PVA fibers within the HPS matrix can lead to increased air-void formations. This phenomenon raises the volume content of large bubbles and increases the average bubble area and diameter, thereby elevating the pore volume fraction within the 500–1200 μm and >1200 μm ranges. Therefore, these microstructural changes reduce the compactness of the HPS matrix, resulting in a decrease in compressive strength and elastic modulus. The compressive strength exhibited a reduction ranging from 10.44% to 15.11%, while the elastic modulus showed a decrease of between 8.09% and 12.67%. Overall, the PVA-HPS mixtures with different mix proportions demonstrated excellent frost resistance, chloride ion penetration resistance, and carbonation resistance. The electrical charge passed ranged from 133 to 370 C, and the carbonation depth varied between 2.04 and 6.12 mm. Although the incorporation of PVA fibers reduced the permeability and carbonation resistance of shotcrete, it significantly mitigated the loss of tensile strength during freeze–thaw cycles. The findings offer insights into optimizing the use of PVA fibers in HPS applications, balancing enhancements in tensile properties with potential impacts on compressive performance.

Enhancing anti-carbonation properties of oil well cement slurry through nanoparticle and cellulose fiber synergy

The anti-carbonation property of oil well cement (OWC) is critical for sealing efficiency of wellbores under geological CO2 sequestration. However, gas migration through OWC around wellbores may lead to a deterioration and failure of the entire storage system. Developing carbon-resistant cement has been the emerging trend in the research community. Previous studies mainly focused on nanoparticles alone to enhance performance of OWC, and the purpose of the research is to explore the synergy of nanoparticles and cellulose fiber (CF) in enhancing engineering properties (e.g., carbonation resistance) of oil well cement slurry. The focus was on investigating compressive strength, permeability, pore structure, and carbonation depth associated with the micro-level texture in a CO2 corrosion environment using X-ray diffraction, Scanning Electron Microscopy, and thermogravimetric analysis methods. Four nanoparticles, namely, nano-SiO2 (NS), nano-TiO2 (NT), nano-Al2O3 (NA), and nano-CaCO3 (NC), were selected for the mixture design. Results indicated that the incorporation of 1∼2 % NPs into the OWC paste resulted in a notable decrease in portlandite and an increase in calcium silicate hydrates, thereby enhancing compressive strength and hydration process. In addition, the single admixture of CF could minimize the formation of cracks in the cement matrix and reduce the average carbonation depth by 54 %. More importantly, the synergy of CF and NP significantly improved the resistance of OWC to carbonation, and the OWC mixed with CF and NS displayed the highest carbonation resistance.