CONSTRUCTION AND BUILDING MATERIALS
·
2025
·
IF 8
Rong Pengjie,Tang Pei,Chen Wei
The effects of different ammonium salts (ammonium carbonate, diammonium hydrogen phosphate, ammonium sulfate, and ammonium chloride) on the carbonation mineralization performance of γ-C 2 S were investigated. Various analytical techniques were employed to characterize the mechanical properties, carbonation product compositions, morphology and pore structure of the hardened matrix. The results indicate that the performance of the hardened matrix after carbonation curing is closely related to the mineralization degree, the types of formed products, and the calcium carbonate structure. The introduction of ammonium salts altered the carbonation products and microstructure of the materials, reducing the Q 4 /Q 3 content of the silica gel and modifying the formation of vaterite, particularly in the systems containing ammonium sulfate, diammonium hydrogen phosphate, and ammonium carbonate. These changes consequently affected the pore structure. Among the different salts, the use of a 2 mol/L ammonium chloride solution showed the most significant improvement in the performance of the hardened material. Compared to the control group, the compressive strength and carbonation degree increased by 42.04 % and 7.33 %, respectively. This enhancement was primarily attributed to the increased calcium carbonate content, which reduced harmful pores and led to a more regular and stable structure of calcite particles. This study identifies key factors influencing the performance changes of γ-C 2 S-based carbonated materials under different ammonium salt dosages, providing new possibilities for the development of high-performance carbon-cured cementitious materials.
研究领域:
材料科学
·
胶凝材料
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二氧化碳封存
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矿物碳化
·
建筑材料
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高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2025
·
IF 8
Yuhan Wang,Qingyuan Xu,Bao Lu,Jinfeng Sun,Zhonglun Zhang,Chuanlin Hu,Guihua Hou
In the preparation of foam concrete (FC), reconciling the contradiction of porosity (or thermal conductivity) and mechanical strength poses a significant challenge. In this paper, the strategy of regulating the carbonation of γ-2CaO·SiO 2 (γ-C 2 S) to form aragonite whiskers for strengthening the pore wall was proposed, thereby achieving the highest possible total porosity while meeting the required compressive strength. The controlled formation of aragonite and its strengthening mechanism of pore wall, as well as the optimum preparation conditions of FC formed by γ-C 2 S carbonation were studied. The results indicated that the CaCO 3 in the pore walls predominantly existed in the form of whisker-like aragonite under the action of modifier MgCl 2 ·6H 2 O, and the mass content of aragonite achieved 53.4 %, almost without calcite. Under the optimum preparation conditions, the thermal conductivity and compressive strength of aragonite foam concrete (AFC) were 0.0496 W/m·K and 0.5 MPa, respectively. Compared with calcite foam concrete (CFC) formed without the regulator, the compressive strength was increased by 150 % and the thermal conductivity was decreased by 5.2 %, it showed that thermal conductivity and mechanical strength were reconciled. Based on pore structure analysis, the formation of aragonite reduced the pore wall porosity (PP) and refined the most probable pore size. Furthermore, the CO 2 absorption rate reached 45.4 % under the carbonation of 84 h. This provides a new perspective for the preparation of low thermal conductivity FC with CO 2 sequestration functionality.
研究领域:
材料科学
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土木工程
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碳封存
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晶体生长
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隔热材料
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高影响因子
Materials
·
2023
·Vol. 16
·期 20
·
IF 3.4
Ziyue Yan,Yaqing Jiang,Kangting Yin,Limeng Wang,Tinghong Pan
This paper investigated the combined effect of chemical activators and nano-SiO2on the hydration reaction and the microstructure of γ-C2S. The hydration reaction of γ-C2S slurry activated with chemical activators (NaHCO3, NaOH, K2CO3, and KOH at 1 mol/L) was enhanced by 1% nano-SiO2. The hydrate reaction rate was determined by isothermal calorimetry, and the hydrated samples were characterized by XRD, TGA/DTG, SEM-EDS, and29Si MAS/NMR. The results revealed a substantial enhancement in the hydration activity of γ-C2S due to the presence of the alkaline activator. Furthermore, nano-SiO2did not alter the composition of γ-C2S hydration products, instead providing nucleation sites for the growth of hydration products. Incorporating nano-SiO2promoted the formation of C-(R)-S-H gel with a low calcium-to-silica ratio and increased its polymerization levels, resulting in more favorable structures. Among all the activators used in this study, potassium salts had a better activation effect than sodium salts. After 28 days of curing, the degree of hydration reaction in the KC+Si group was 48% and about 37% for the NHC+Si group. Whereas, the KH+Si and NH+Si groups only reached approximately 20% after the same hydration duration.
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DOI
高影响因子
Case Studies in Construction Materials
·
2026
·
IF 6.9
Pengjie Rong,Pei Tang
CO 2 curing technology for construction materials faces three major challenges: limited CO 2 diffusion due to the dense CaCO 3 layer, inefficient reaction kinetic, and internal stresses induced by volumetric expansion during the carbonation curing process. This study introduces a layered structure strategy employing PAM hydrogel as interlayers between γ-C 2 S layers to address these limitations through the combined functions of PAM incorporation and layered structural design. Layered structure specimens achieved compressive strength of 127.60 MPa, flexural strength of 23.68 MPa, and carbonation degree of 41.8%, representing improvements of 114.63%, 29.05%, and 9.9 percentage points, respectively, over conventional compaction structure. Multiscale characterization indicated that PAM incorporation and its layered spatial arrangement contributed differently to carbonation behavior and mechanical performance. First, the PAM interlayer formed a CO 2 permeation network through horizontal layer channels, enabling carbonation to penetrate beyond surface regions. Second, the polyacrylamide hydrogel maintains optimal humidity conditions coupled with interfacial Ca 2 + -carboxylate coordination accelerates ion leaching and reaction kinetics. Third, the polyacrylamide layer dissipates volumetric stresses during the reaction process through reversible deformation and energy dissipation, thereby enhancing material toughness and strain-bearing capacity. This layered manufacturing strategy provides a viable route to simultaneously optimize CO 2 sequestration and mechanical performance, offering new perspectives for developing carbonation mineralized materials and advancing CO 2 curing technology toward industrial application.
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高影响因子
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