Effect of Dry–Wet Ratio on Properties of Concrete Under Sulfate Attack

Guo, Jinjun; Wang, Kun; Guo, Ting; Yang, Zhengxian; Zhang, Peng

doi:10.3390/ma12172755

Cited by 47 publications

(26 citation statements)

References 33 publications

(39 reference statements)

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“…If one compares these values, it is possible to conclude that ISR observed in concrete cores imposed a severe decrease in dynamic modulus of concrete (close to −45%). This fact represents the cracking process observed in the pile cap surface during the visual inspections and certifies the efficiency of this parameter as a good indicator of concrete damage due to ISRs [27,[41][42][43][44][45][46][47].…”

Section: Summary Of Isr In Concrete Cores Dynamic Modulus Elasticitymentioning

confidence: 73%

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Diagnosis and Assessment of Deep Pile Cap Foundation of a Tall Building Affected by Internal Expansion Reactions

et al. 2021

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Early deterioration of reinforced concrete foundations has been often reported in recent years. This process is usually characterized by an extensive mapping cracking process on concrete surfaces that results from several types of Internal Swelling Reaction (ISR). In this paper, a real case study of a tall reinforced concrete building with a severe deterioration process installed in its deep foundations is discussed. Laboratory tests were performed in concrete drilled cores extracted from a deep pile cap block 19 years after the beginning of construction. Tests to assess the compressive strength, the static and the dynamic modulus of elasticity, the gas permeability, and electron microscopy scanning to find out the primary mechanism responsible for the deterioration observed during in situ inspections. Chemical alterations of materials were observed in concrete cores, mainly due to Delayed Ettringite Formation (DEF), which significantly affected the integrity and durability of the structure. Dynamic modulus of elasticity showed to be a better indicator of damage induced by ISR in concrete than compressive strength. Procedures to strengthen the deteriorated elements using prestressing proved to be an efficient strategy to recover the structural integrity of pile caps deteriorated due to expansions due to ISR.

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Section: Summary Of Isr In Concrete Cores Dynamic Modulus Elasticitymentioning

confidence: 73%

“…In fact, the usual values of this parameter for undamaged concrete are in the range of 10 −18 -10 −17 m [32,33]. Values of porosity tests indicated 11.29% and 9.76% for the two concrete cores investigates, which are higher than those available in literature [8,44].…”

Section: Gas Permeabilitymentioning

confidence: 83%

Diagnosis and Assessment of Deep Pile Cap Foundation of a Tall Building Affected by Internal Expansion Reactions

et al. 2021

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“…The grey relational analysis was applied to analyze the durability of admixture concrete, which were respectively added with mono MK, mono UFA, and composite MK and UFA. Ten different kinds of concretes were used in this experiment, and the micro analysis has been carried out respectively on ordinary concrete [ 38 ], MK concrete [ 20 ], and UFA concrete [ 39 ]. which experienced sulfate erosion.…”

Section: Introductionmentioning

confidence: 99%

A Research on Durability Degradation of Mineral Admixture Concrete

2021

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In order to study the degradation laws and mechanisms of admixture concretes with single-added SO42− and composite of Mg2+ and SO42−, respectively, the durability tests were conducted on three types of mineral admixture concretes (concretes with single-added metakaolin (MK), single-added ultra-fine fly ash (UFA), and composite of metakaolin and ultra-fine fly ash (MF), and one reference concrete. In these tests, the 10% Na2SO4 solution and the 10% MgSO4 solution were used as the erosion medium, and the drying-wetting circle method was applied. It can be seen from the compressive tests and grey relational analysis that the MK admixture can improve the anti-Na2SO4-erosion capability of the concrete significantly, but weaken its anti-MgSO4-erosion capability; the UFA admixture can improve both the anti-Na2SO4-erosion and the anti-MgSO4-erosion capability of the concrete; and the composite admixture has superimposed effects and can enhance erosion resistance against these two erosion mediums. The phase composition and the changes of the macro morphology and the micro structure during the erosion process caused by mono sulfate ions and complex ions has been observed through X-ray diffraction (XRD), FTIR spectrum (FTIR), and scanning electron microscope (SEM), based on which it was determined that the erosion of single-added SO42− ions can produce erosive outputs of ettringite, gypsum, and mirabilite in the concrete, and cause corner scaling or deformation. Mg2+ and SO42− reacted in the concrete and produced brucite, M-S-H, ettringite, and gypsum, etc. The erosion of complex ions can cause scaling of the cement mortar and aggregate from the surface or the desquamation of corners.

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“…Many researchers have made a lot of achievements in the study of sulfate-eroded concrete [ 10 , 11 , 12 , 13 , 14 ]. But due to the differences in the simulated experimental environment [ 15 , 16 , 17 , 18 ], the selected test method [ 19 , 20 , 21 ], and the concrete mix ratio used in the test [ 22 , 23 ], etc., up to now, there is no unified test system.…”

Section: Introductionmentioning

confidence: 99%

Study on the Deterioration of Concrete under Dry–Wet Cycle and Sulfate Attack

et al. 2020

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In order to study the deterioration and mechanism of dry–wet cycles and sulfate attack on the performance of concrete in seaside and saline areas, the deterioration of compressive strength of concrete with different water cement ratios under different erosion environments (sodium sulfate soaking at room temperature and coupling of dry–wet cycling and sodium sulfate) was studied here. At the same time, ICT (industrial computed tomography) and NMR (nuclear magnetic resonance) techniques were used to analyze the internal pore structure of concrete under different erosion environments. The results show that the compressive strength under different erosion environments increases first and then decreases, and the dry–wet cycle accelerates the sulfate erosion. With the increase of dry and wet cycles, larger pores are filled with erosion products and developed into small pores in the early stage of erosion; in the later stage of erosion, the proportion of larger pores increases, and cracks occur inside the sample. In the process of sulfate soaking and erosion, the smaller pores in the concrete account for the majority. As the sulfate erosion continues, the T2 spectrum distribution curve gradually moves right, and the signal intensity of the larger pores increases.

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Effect of Dry–Wet Ratio on Properties of Concrete Under Sulfate Attack

Cited by 47 publications

References 33 publications

Diagnosis and Assessment of Deep Pile Cap Foundation of a Tall Building Affected by Internal Expansion Reactions

Diagnosis and Assessment of Deep Pile Cap Foundation of a Tall Building Affected by Internal Expansion Reactions

A Research on Durability Degradation of Mineral Admixture Concrete

Study on the Deterioration of Concrete under Dry–Wet Cycle and Sulfate Attack

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