Experimental Determination of Fracture Energy by RILEM Method

Uday, Naik Partha

doi:10.9790/1813-060301106115

Cited by 6 publications

(2 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These three fracture parameters, G F , G f , and f t ’ (or l ch , l 1 , and f t ’ ) are sufficient to generate a cohesive model of concrete material. Similar measurements for evaluating the fracture energy and l ch have been reported by many researchers [23,24,25,26,27,28,29,30,31].…”

Section: Introductionsupporting

confidence: 75%

Fracture Parameters of Cement Mortar with Different Structural Dimensions Under the Direct Tension Test

2019

View full text Add to dashboard Cite

In this paper, we measured the fracture properties of cement mortar—which is composed of sand and has a nearly constant diameter—using a direct tension test. Four double-notched mortar bar specimens with different structural dimensions were assessed. The failure load, load-crack mouth opening displacement, and elongation of the gauge length were measured under direct displacement control. The fractured surfaces were scanned and measured so that we could calculate the tensile strength accurately and determine the fracture energy and characteristic length. The average ratio of total fracture energy (GF) to specific fracture energy (Gf) was 1.94; this was lower than the typical value for concrete, of 2.5. The direct tension test showed that the double-notched mortar specimens had a smaller fracture processing zone after the initiation of tensile cracks, so the tail portion of the softening branch was small. This decreased the GF/Gf ratio. We verified this result based on a nonlinear fracture mechanics simulation and found that it agreed well with our experimental results. We also investigated the size effects of four different scaled specimens while holding the ratio of structural dimension, d, and notch length, a is constant, so that there was no shape effect. The traditional linear elastic fracture mechanics (LEFM) prediction and Bažant’s size effect law yield a gradient closer to 1/2 in the case of relatively large specimens. In the case of our cement mortar specimens, this prediction was not supported, where the value of the slope was 1/0.727. This was unexpected because LEFM predicts strong size effects. One possible explanation for this result is that the size effects of concrete are most often evaluated using a bending test; also, concrete has a larger maximum aggregate size than mortar. Due to the random heterogeneities in aggregate distribution, higher tail energies may be seen for concrete, leading to differences in the GF/Gf ratio. At the same time, the peak tensile stress could be affected by the relationship between structural dimensions and aggregate size.

show abstract

Section: Introductionsupporting

confidence: 75%

Fracture Parameters of Cement Mortar with Different Structural Dimensions Under the Direct Tension Test

2019

View full text Add to dashboard Cite

show abstract

“…Dengan berkembangnya teknologi beton HPC, efisiensi komponen struktur menjadi lebih optimal. Struktur beton umumnya terdiri dari banyak retakan mikro yang dapat mengakibatkan retaknya struktur beton akibat beban pada kondisi layan, beban tidak disengaja atau paparan kondisi lingkungan (Uday, 2017). Dengan demikian, retakan mikro pada beton dapat menjadi sumber potensial perambatan retak yang mengarah pada keruntuhan struktur.…”

Section: Pendahuluanunclassified

Aplikasi Size Effect Law Pada Beton Marine dengan Pola Bukaan Tarik

Supazaein¹,

Muin²

2021

JTS ITB

View full text Add to dashboard Cite

AbstrakPengembangan infrastruktur di bidang maritim adalah salah satu strategi untuk mengembangkan perekonomian. Beton marine banyak digunakan sebagai material struktur pada pembangunan infrastruktur di bidang maritim tersebut. Beton marine harus menggunakan beton high performance concrete (HPC). Dengan berkembangnya teknologi beton HPC pengoptimalan efisiensi komponen struktur menjadi lebih signifikan.Pada perencanaan pelaksanaan pembangunan khususnya pada tahap analisa struktur, jarang sekali direncanakan kekuatan terhadap mekanika fraktur yang seharusnya juga didesain agar keruntuhan secara fraktur bisa diatasi. penelitian ini mengkaji aplikasi size effect law pada beton HPC pada balok dengan berbagai ukuran yang sudah ditentukan (small, medium dan high) untuk memperoleh nilai energy fraktur (Gf). Hasil penelitian ini dapat berkontribusi dalam penerapam metode untuk mendapatkan nilai parameter dari kinerja fraktur. selain itu, data parameter dapat digunakan dalam mengkalibrasi analisa numerik elemen struktur berbasis fraktur energi agar dapat dipastikan kinerja struktur yang sesungguhnya.Hasil pengujian menunjukkan energi fraktur pada benda uji set II (rasio takik terhadap tinggi sample = 1/6) lebih besar 8,4% dari benda uji set I (rasio takik terhadap tinggi sample = 1/3). Factor geometri dan kemiringan pada garis regresi (A) menurun selaras dengan menurunnya rasio takik. Dari angka keruntuhan nilai berada pada range 0,1 < < 10 yang menandakan material didesain harus dengan kriteria nonlinear fracture mechanic.Kata-kata Kunci: Beton marine, mekanika fraktur, size effect law, nonlinear fracture mechanics AbstractInfrastructure development in the maritime sector is one strategy for developing the economy. Marine concrete is widely used as a structural material in infrastructure development in the maritime sector. Marine concrete must use high performance concrete (HPC). With the development of HPC concrete technology, optimization of the efficiency of structural components has become more significant.In the construction implementation planning, especially at the structural analysis stage, it is rare to plan the strength of the fracture mechanics which should also be designed so that fracture collapse can be overcome. This study examines the application of size effect law on HPC concrete on beam of various predetermined sizes (small, medium and high) to obtain the fracture energy value (Gf). The results of this study can contribute to the application of the method to obtain parameter values of fracture performance. In addition, parameter data can be used in calibrating the numerical analysis of energy fracture based structural elements in order to ascertain the actual performance of the structure.The results showed that fracture energy in specimen set II (ratio of notches to depth = 1/6) was 8.4% greater than specimen set I (ratio of notches to sample height = 1/3). The geometric factor and slope of the regression line (A) decreased in line with the decreasing notch ratio. From the brittleness number, the value of Î² is in the range 0.1 <Î² <10 which indicates that the material should designed with nonlinear fracture mechanic criteria.Key words: marine concrete, fracture mechanics, size effect law, nonlinear fracture mechanics

show abstract