Experimental study on water absorption of unsaturated concrete: w/c ratio, coarse aggregate and saturation degree

Yang, Lin; Liu, Guojian; Gao, Danying; Zhang, Chunxiao

doi:10.1016/j.conbuildmat.2020.121945

Cited by 53 publications

(10 citation statements)

References 28 publications

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Section: Resultsmentioning

confidence: 99%

“…The water absorption and porosity of CG100 were 15.9% and 6.1%, respectively, which were two or three times as much as those of CG0. The pore structure of the CG and a large w/b were the main reasons for the increases in water absorption and porosity [21]. Figure 8 shows the back-scattering electron microscope (BSE) images of the micro structures of specimens with different CG replacement ratios on day 28.…”

Section: Mechanical Test and Water Absorptionmentioning

confidence: 99%

See 1 more Smart Citation

Mechanical Properties of Reactive Powder Concrete with Coal Gangue as Sand Replacement

Luo¹,

Wang

et al. 2022

Materials

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Coal gangue (CG) represents a huge amount of industrial solid waste in China, and usually is used as a coarse aggregate to produce low-strength coal-gangue-based concrete. In this paper, in order to prove the possibility to obtain a higher-strength concrete with a higher CG utilization rate, reactive powder concrete (RPC) with coal gangue as a sand replacement at different replacement ratios was studied. RPC samples were prepared by replacing natural river sand (RS) with CG sand at different CG/RS weight ratios from 0–100% at intervals of 25%. Mechanical tests were carried out, and the microstructure features of RPC samples at 28 days were characterized. The test results showed that strong back shrinkage of strength existed. On days 7 and 14, the flexural strengths of samples with CG/RS replacement ratios of 0–75% fluctuated around the mean value. Strengths of samples with a CG/RS replacement ratio of 100% dropped off. However, on day 28, the flexural strengths of samples with CG were all lower than the strengths of samples on days 7 and 14. The flexural strengths and compressive strengths of the RPC with a CG/RS replacement ratio of 100% on day 14 were 14.09 MPa and 37.03 MPa, respectively, which decreased to 6.42 MPa and 28.44 MPa, respectively, on day 28. Compared with natural river sand, CG sand reduced the working performance, compressive strength, and flexural strength of RPC. Microscopic analysis showed that on day 28, increasing the CG replacement ratio could inhibit cement hydration, weaken the interface transition zone, and lead to the degradation of the RPC’s performance. Modification of CG sand would be helpful to obtain higher-strength concrete.

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Section: Resultsmentioning

confidence: 99%

Section: Mechanical Test and Water Absorptionmentioning

confidence: 99%

Mechanical Properties of Reactive Powder Concrete with Coal Gangue as Sand Replacement

Luo¹,

Wang

et al. 2022

Materials

View full text Add to dashboard Cite

show abstract

“…It is therefore necessary to consider the presence of two types of water: the one that occupies the porosity of the aggregate and the superficial one that causes the aggregate to appear wet. The determination of the theoretical amount of water to be added to the mixture will be depleted of the amount of surface water that the aggregate has, hence the importance of a correct calculation of the absorption value of each aggregate, as it can certainly affect the predetermined w/c ratio [ 58 , 59 ].…”

Section: Resultsmentioning

confidence: 99%

Petrographic and Physical-Mechanical Investigation of Natural Aggregates for Concrete Mixtures

2021

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The availability of different lithology with which concrete can be packaged could create substantial questions on the differences that they can provide to the same mixture. Different kinds of aggregates were analyzed individually to investigate their main characteristics, which allowed us to package five types of concrete mixtures. These five mixtures were compared to each other through compressive strength values. Furthermore, it was considered microscopically what possible differences could exist between these different mixtures, for example, differences in the cement/aggregate reaction. The chemical characterization of the aggregates, used as the skeleton of the cement mixes, was proposed as an important investigative phase in order to better understand the differences in the geotechnical and physical-mechanical characteristics and to verify the presence of any harmful phases for the durability of the concrete.

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“…The expansion effect of these two products can improve the compactness of concrete and increase the strength of concrete. However, the 15% and 20% fly ash content are relatively low, and the active effect of fly ash has not been fully reflected in the initial stage, so the improvement of the sulfate corrosion performance of concrete is not obvious [25]. As the erosion time increases, the active silica and alumina contained in the fly ash react with the calcium hydroxide in the concrete to form hydrated calcium silicate and hydrated calcium aluminate.…”

Section: Compressive Strengthmentioning

confidence: 99%

Determining the Mineral Admixture and Fiber on Mechanics and Fracture Properties of Concrete under Sulfate Attack

Guo

Wang

Qi³

2021

JMSE

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The concrete structure in the coastal area suffers from the combined erosion of sulfate and dry–wet cycles. In this study, in order to modify ordinary concrete, fly ash, slag powder, silica fume and polyester fiber are added separately. The crack resistance of concrete was studied through mechanical performance test and three-point bending fracture test of notched beam under sulfate dry–wet cycles. The load-crack opening displacement (P-CMOD) curve characteristics, fracture toughness and fracture energy of modified concrete after corrosion are calculated and analyzed. Results reveal that the P-CMOD curve of modified concrete after corrosion has gone through four stages of damage: initial bending section, proportional elastic section, stable expansion section and softening section. With the increase of dry–wet cycles, the overall corrosion resistance and toughening coefficient of modified concrete increases first and then decreases. Adding 25% fly ash can significantly enhance the fracture toughness of concrete in the initial stage. The addition of polyester fiber and slag is beneficial to the improvement of the instability toughness and fracture energy of the concrete in the later stage.

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Experimental study on water absorption of unsaturated concrete: w/c ratio, coarse aggregate and saturation degree

Cited by 53 publications

References 28 publications

Mechanical Properties of Reactive Powder Concrete with Coal Gangue as Sand Replacement

Mechanical Properties of Reactive Powder Concrete with Coal Gangue as Sand Replacement

Petrographic and Physical-Mechanical Investigation of Natural Aggregates for Concrete Mixtures

Determining the Mineral Admixture and Fiber on Mechanics and Fracture Properties of Concrete under Sulfate Attack

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