Effect of wetting–drying cycles on mode I and mode II fracture toughness of cement mortar and concrete

Dehestani, A.; Hosseini, Mehdi; Beydokhti, Alireza Taleb

doi:10.1016/j.tafmec.2019.102448

Cited by 35 publications

(5 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On their basis, it was found that microcracks develop in concrete structures during the loading process, which leads to a gradual loosening of the material. Thus, fracture toughness of brittle materials should be examined under various load states, e.g., [ 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 ].…”

Section: Purpose and Scope Of The Experimental Researchmentioning

confidence: 99%

Studies of Fracture Toughness in Concretes Containing Fly Ash and Silica Fume in the First 28 Days of Curing

Golewski

Gil

2021

Materials

View full text Add to dashboard Cite

This paper presents the results of the fracture toughness of concretes containing two mineral additives. During the tests, the method of loading the specimens according to Mode I fracture was used. The research included an evaluation of mechanical parameters of concrete containing noncondensed silica fume (SF) in an amount of 10% and siliceous fly ash (FA) in the following amounts: 0%, 10% and 20%. The experiments were carried out on mature specimens, i.e., after 28 days of curing and specimens at an early age, i.e., after 3 and 7 days of curing. In the course of experiments, the effect of adding SF to the value of the critical stress intensity factor—KIcS in FA concretes in different periods of curing were evaluated. In addition, the basic strength parameters of concrete composites, i.e., compressive strength—fcm and splitting tensile strength—fctm, were measured. A novelty in the presented research is the evaluation of the fracture toughness of concretes with two mineral additives, assessed at an early age. During the tests, the structures of all composites and the nature of macroscopic crack propagation were also assessed. A modern and useful digital image correlation (DIC) technique was used to assess macroscopic cracks. Based on the conducted research, it was found the application of SF to FA concretes contributes to a significant increase in the fracture toughness of these materials at an early age. Moreover, on the basis of the obtained test results, it was found that the values of the critical stress intensity factor of analyzed concretes were convergent qualitatively with their strength parameters. It also has been demonstrated that in the first 28 days of concrete curing, the preferred solution is to replace cement with SF in the amount of 10% or to use a cement binder substitution with a combination of additives in proportions 10% SF + 10% FA. On the other hand, the composition of mineral additives in proportions 10% SF + 20% FA has a negative effect on the fracture mechanics parameters of concretes at an early age. Based on the analysis of the results of microstructural tests and the evaluation of the propagation of macroscopic cracks, it was established that along with the substitution of the cement binder with the combination of mineral additives, the composition of the cement matrix in these composites changes, which implies a different, i.e., quasi-plastic, behavior in the process of damage and destruction of the material.

show abstract

Section: Purpose and Scope Of The Experimental Researchmentioning

confidence: 99%

Studies of Fracture Toughness in Concretes Containing Fly Ash and Silica Fume in the First 28 Days of Curing

Golewski

Gil

2021

Materials

View full text Add to dashboard Cite

show abstract

“…In structures made of unreinforced concrete there is a possibility of brittle failure due to tensile or shear stresses in the element’s sections, and microcracks in the material’s structure. Fracture mechanics deals with the problems of brittle failure, whereas the basic parameter of fracture toughness is a critical stress intensity factor— K αc (α = I, II or III, depending on the adopted mode fracture), e.g., [ 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 ].…”

Section: The Importance Of Researchmentioning

confidence: 99%

Changes in the Fracture Toughness under Mode II Loading of Low Calcium Fly Ash (LCFA) Concrete Depending on Ages

Golewski

2020

Materials

View full text Add to dashboard Cite

This study investigated the influence of the curing time on the fracture toughness of concrete produced with different content of low calcium fly ash (LCFA). During the study, the amounts of 20% and 30% of pozzolanic additive were used. In order to observe the effect of the applied pozzolanic additive on the analyzed concrete properties, the obtained results were compared with the values obtained for the reference concrete. Compressive strength—fcm and fracture toughness, by using mode II loading—KIIc (shearing), were determined between the 3rd and 365th days of curing. In the course of experiments, changes in the development of cracks in individual series of concrete were also analyzed. In addition, the microstructures of all composites and the nature of macroscopic crack propagation in mature concretes were assessed. It was observed that the greatest increase in fracture toughness at shear was in the case of reference concrete during the first 28 days, whereas, in the case of concretes containing LCFA, in the period of time above 4 weeks. Furthermore, concrete without the LCFA additives were characterized by a brittle fracture. In contrast to it, concretes with LCFA additives are mainly characterized by a quasi-plastic process of failure. Moreover, most of the samples showed a typical pattern of the destruction that occurs as a result of shearing. The presented test results may be helpful in selecting the composition of concrete mixtures containing LCFA to be used in concrete and reinforced concrete structures subjected to shear loads.

show abstract

“…e microstructure analysis shows that the corrosion depth of sulfate erosion increases with the increase of dry-wet cycles. Dehestani et al' [22] experimental study found that as the number of wet and dry cycles increases, the tensile and shear fracture toughness of concrete decreases. Daqing et al [23] studied the relationship between compressive strength and splitting strength of recycled concrete under the action of dry-wet cycles.…”

Section: Introductionmentioning

confidence: 99%

Research on the Creep Characteristics of Thermal Insulation Shotcrete under the Action of Temperature and Humidity Circulation

Zhang

Wang

Liu

et al. 2021

Advances in Civil Engineering

View full text Add to dashboard Cite

In order to explore the creep characteristics of thermal insulation shotcrete under the action of temperature and humidity circulation, a series of uniaxial compression creep tests were carried out with different cycles of temperature and humidity and hierarchical loading conditions. The test results show that the axial creep deformation and creep strain of the thermal insulation shotcrete specimens increase with the increase of the number of drying and wetting cycles under normal temperature water bath condition. After 28 cycles, the deformation value becomes larger obviously, and the creep strain increases greatly in the precycle period. The thermal insulation shotcrete axial steady-state creep rate increases nonlinearly with the increase of the number of drying and wetting cycles under different stress levels. When the number of adjacent cycles is 0–3, the average increase is larger, and the axial steady-state creep rate of thermal insulation shotcrete for 28 cycles increases with the increase of water bath temperature. The instantaneous deformation modulus of thermal insulation shotcrete decreases logarithmically with the increase of the number of drying and wetting cycles, and the total deterioration degree of the average instantaneous deformation modulus increases gradually, but the deterioration degree between adjacent cycles decreases successively. The thermal insulation shotcrete specimens with 3 cycles of fracture were mainly stretched, and with the increase of the water bath temperature, the specimen was damaged by shear failure. When the water bath temperature is 40°C, the fracture degree of the specimen increases first and then decreases with the increase of the number of cycles.

show abstract

Effect of wetting–drying cycles on mode I and mode II fracture toughness of cement mortar and concrete

Cited by 35 publications

References 37 publications

Studies of Fracture Toughness in Concretes Containing Fly Ash and Silica Fume in the First 28 Days of Curing

Studies of Fracture Toughness in Concretes Containing Fly Ash and Silica Fume in the First 28 Days of Curing

Changes in the Fracture Toughness under Mode II Loading of Low Calcium Fly Ash (LCFA) Concrete Depending on Ages

Research on the Creep Characteristics of Thermal Insulation Shotcrete under the Action of Temperature and Humidity Circulation

Contact Info

Product

Resources

About