Nuclear Magnetic Resonance Study on Concrete Pore Structure Evolution Under Different Curing Environments

Chen, Junhao; Li, Yanlong; Zhou, Heng; Li, Yang; Guo, Hanyu

doi:10.1007/s11837-022-05221-3

Cited by 14 publications

(2 citation statements)

References 47 publications

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“…Prior to measurement, concrete samples subjected to 0 and 90 dry-wet cycles were extracted using a concrete core drill and then treated with vacuum water saturation for 24 h using a vacuum saturation device (E-1010, Hitachi, Tokyo, Japan). In accordance with NMR principles, NMR data were collected using the CPMG pulse sequence [56][57][58][59]. For porous materials, the relationship between surface relaxation and pore structure is given by Formula (4) [60].…”

Section: Nmr Testmentioning

confidence: 99%

Under Sulfate Dry–Wet Cycling: Exploring the Symmetry of the Mechanical Performance Trend and Grey Prediction of Lightweight Aggregate Concrete with Silica Powder Content

Wang,

Chen,

Wang

2024

Symmetry

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In order to improve the mechanical properties and durability of lightweight aggregate concrete in extreme environments, this study utilized Inner Mongolia pumice as the coarse aggregate to formulate pumice lightweight aggregate concrete (P-LWAC) with a silica powder content of 0%, 2%, 4%, 6%, 8%, and 10%. Under sulfate dry–wet cycling conditions, this study mainly conducted a mass loss rate test, compressive strength test, NMR test, and SEM test to investigate the improvement effect of silica powder content on the corrosion resistance performance of P-LWAC. In addition, using grey prediction theory, the relationship between pore characteristic parameters and compressive strength was elucidated, and a grey prediction model GM (1,3) was established to predict the compressive strength of P-LWAC after cycling. Research indicates that under sulfate corrosion conditions, as the cycle times and silica powder content increased, the corrosion resistance of P-LWAC showed a trend of first increasing and then decreasing. At 60 cycles, P-LWAC with a content of 6% exhibited the lowest mass loss rate and the highest relative dynamic elastic modulus, compressive strength, and corrosion resistance coefficient. From the perspective of data distribution, various durability indicators showed a clear mirror symmetry towards both sides with a silica powder content of 6% as the symmetrical center. The addition of silica fume reduced the porosity and permeability of P-LWAC, enhanced the saturation degree of bound fluid, and facilitated internal structural development from harmful pores towards less harmful and harmless pores, a feature most prominent at the 6% silica fume mixing ratio. In addition, a bound fluid saturation and pore size of 0.02~0.05 μm/% exerted the most significant influence on the compressive strength of P-LWAC subjected to 90 dry–wet cycles. Based on these two factors, grey prediction model GM (1,3) was established. This model can accurately evaluate the durability of P-LWAC, improving the efficiency of curing decision-making and construction of concrete materials.

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Section: Nmr Testmentioning

confidence: 99%

Under Sulfate Dry–Wet Cycling: Exploring the Symmetry of the Mechanical Performance Trend and Grey Prediction of Lightweight Aggregate Concrete with Silica Powder Content

Wang,

Chen,

Wang

2024

Symmetry

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“…Pore structures exist in aggregates, cementitious materials, and interface transition zones and can be divided into primary and secondary pores. The internal pore structure possesses the characteristics of large morphological differences, disorderly distribution, and wide pore size coverage, which significantly impact the strength, deformation, and durability of concrete (Luna-Galiano et al, 2016;Zhang et al, 2020;Liu et al, 2021;Chen et al, 2022;Ren et al, 2022). However, not all pore structures adversely affect concrete performance.…”

Section: Influence Mechanism Of Pore Distribution On Mechanical Stren...mentioning

confidence: 99%

The mechanical properties of concrete in water environment: A review

Wang

Sun

et al. 2022

Front. Mater.

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The service performance of concrete structures in a water environment differs from that in a normal environment. An accurate evaluation of the mechanical properties and service status of wet concrete is related to the reliable design and safe operation of concrete structures, e.g., hydraulics, marine engineering, bridges, and tunnels. To promote the application of new and high-performance concrete to complex water environments and grasp the future development trend, the research progress on the service performance of concrete in water environments was reviewed worldwide. Starting from the internal water content of concrete, the existing research is combed, the influence of water content, water pressure, and loading rate on the static and dynamic characteristics of concrete in a water environment is summarized, and the influence mechanism is analyzed. The literature review demonstrates that the static compressive strength of wet concrete is lower than that of dry concrete; however, the elastic modulus improves. With an increase in the strain rate, the compressive strength of wet and dry concretes improves, and the rate sensitivity of the wet concrete is greater than that of the normal concrete. Pore structure characteristics mainly affect the static strength of the wet concrete. The improvement in the dynamic strength of the wet concrete is caused by the combined effect of the concrete rate sensitivity, “Stefan” effect, and water pressure.

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Pore structure, mechanical property and permeability of concrete under sulfate attack exposed to freeze–thaw cycles

Xue,

Peng,

Alam

et al. 2024

Archiv.Civ.Mech.Eng

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Nuclear Magnetic Resonance Study on Concrete Pore Structure Evolution Under Different Curing Environments

Cited by 14 publications

References 47 publications

Under Sulfate Dry–Wet Cycling: Exploring the Symmetry of the Mechanical Performance Trend and Grey Prediction of Lightweight Aggregate Concrete with Silica Powder Content

Under Sulfate Dry–Wet Cycling: Exploring the Symmetry of the Mechanical Performance Trend and Grey Prediction of Lightweight Aggregate Concrete with Silica Powder Content

The mechanical properties of concrete in water environment: A review

Pore structure, mechanical property and permeability of concrete under sulfate attack exposed to freeze–thaw cycles

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