DOI•
Effets of Steel Fiber Contents on Flexural Creep Behavior of High-Strength Concrete
01 Jan 2020-Vol. 24, Iss: 2, pp 111-118
TL;DR: In this paper, the flexural creep behavior of hooked-end steel fiber reinforced high-strength concrete was evaluated to investigate the steel fiber content influence on long-term behavior of flexural members.
Abstract: In this paper, the flexural creep behavior of hooked-end steel fiber reinforced high-strength concrete was evaluated to investigate the steel fiber content influence on long-term behavior of flexural members. An experimental program consisted of nine prismatic beam specimens with dimensions of 150 × 150 × 600mm reinforced with different contents of steel fiber (0, 0.75 and 1.5% at the volume fraction). To introduce flexural creep loading to notched prismatic beam specimens, a four-point bending test setup was used. The sustained load with 40% of the flexural strength was applied by means of a lever system and controlled by a load cell for 90 days. During sustained loading, crack mouth opening displacement (CMOD) was monitored. Conventional flexural test after creep tests were carried out to evaluate the residual capacity of each specimen. Test results showed that steel fiber content has a significant effect on the flexural creep behavior of high-strength concrete and long-term flexural load with 40% of flexural strength doesn’t generate negative effects on the residual capacity of steel fiber reinforced high-strength concrete.
Citations
More filters
TL;DR: In this paper, a modified model of ACI-209 based on test result was applied to estimate long period shortening of vertical members exactly, it is designed to modify and suggest the optimal creep model based on various data accumulated during construction, in the future.
Abstract: The construction of super tall building which structure is RC and must be certainly considered on column shortening estimation and construction reflected concrete creep has been increased. Regarding the Fck 60~80MPa grade high strength concrete applied in the domestic super tall building project, the mechanical properties and creep deflection according to curing conditions(Drying creep/Basic creep) were reviewed in this research. Results of compressive strength and elastic modulus under sealed curing condition were 5% higher than unsealed condition and difference of results according to the curing condition was increased over time. Autogenous and drying shrinkage tendency showed adversely in the case of high strength concrete. Additionally, creep modulus under unseal curing condition was evaluated 2~3 times higher than sealed condition. Modified model of ACI-209 based on test result was applied to estimate long period shortening of vertical members(such as Core Wall/Mega Column) exactly, it is designed to modify and suggest the optimal creep model based on various data accumulated during construction, in the future.
4 citations
DOI•
01 Jan 2012
TL;DR: In this article, an empirical and mechanical model of polymer concrete tension creep using long-term experimental results and mathematical development is proposed to evaluate the deformation of the material under sustained loading conditions, and the proposed model has been used successfully to predict creep deformations at a stress level that was 20 percent of the ultimate strength and viscoelastic behavior of recycled-PET polymer concrete is linear of stress level up to 30 percent.
Abstract: In recent years, polymer concrete based on polyester resin have been widely generalized and the research of polymer concrete have been actively pursued by the technical innovations. Polymer concrete is a composite consisting of aggregates and an organic resin binder that hardens by polymerization. Polymer concrete are stronger by a factor of three or more in compression, a factor of four to six in tension and flexural and a factor of two in impact when compared with portland cement concrete. In view of the growing use of polymer concrete, it is important to study the physical characteristics of the material, emphasizing the short term properties as well as long term mechanical behavior. If polymer concrete is to be used in flexural load-bearing application such as in beam, it is imperative to understand the deformation of the material under sustained loading conditions. This study is proposed to empirical and mechanical model of polymer concrete tension creep using long-term experimental results and mathematical development. The test results showed that proposed model has been used successfully to predict creep deformations at a stress level that was 20 percent of the ultimate strength and viscoelastic behavior of recycled-PET polymer concrete is linear of stress level up to 30 percent. It is expected that the present model allows more realistic evaluation of varying stresses in polymer concrete structures with a constant loading.
1 citations
References
More filters
01 Jan 2011
TL;DR: The Building Code Requirements for Structural Concrete (Code) as mentioned in this paper covers the materials, design, and construction of structural concrete used in buildings and where applicable in nonbuilding structures, including the strength evaluation of existing concrete structures.
Abstract: The “Building Code Requirements for Structural Concrete” (“Code”) covers the materials, design, and construction of structural concrete used in buildings and where applicable in nonbuilding structures. The Code also covers the strength evaluation of existing concrete structures. Among the subjects covered are: contract documents; inspection; materials; durability requirements; concrete quality, mixing, and placing; formwork; embedded pipes; construction joints; reinforcement details; analysis and design; strength and serviceability; flexural and axial loads; shear and torsion; development and splices of reinforcement; slab systems; walls; footings; precast concrete; composite flexural members; prestressed concrete; shells and folded plate members; strength evaluation of existing structures; provisions for seismic design; structural plain concrete; strut-and-tie modeling in Appendix A; alternative design provisions in Appendix B; alternative load and strength reduction factors in Appendix C; and anchoring to concrete in Appendix D. The quality and testing of materials used in construction are covered by reference to the appropriate ASTM standard specifications. Welding of reinforcement is covered by reference to the appropriate American Welding Society (AWS) standard. Uses of the Code include adoption by reference in general building codes, and earlier editions have been widely used in this manner. The Code is written in a format that allows such reference without change to its language. Therefore, background details or suggestions for carrying out the requirements or intent of the Code portion cannot be included. The Commentary is provided for this purpose. Some of the considerations of the committee in developing the Code portion are discussed within the Commentary, with emphasis given to the explanation of new or revised provisions. Much of the research data referenced in preparing the Code is cited for the user desiring to study individual questions in greater detail. Other documents that provide suggestions for carrying out the requirements of the Code are also cited.
2,239 citations
TL;DR: In this paper, a study of the time-dependent behaviour of pre-cracked macro-synthetic fiber reinforced concrete (MSFRC) subjected to uni-axial tensile sustained loading was conducted.
Abstract: The increased energy absorption capacity of fibre reinforced concrete (FRC) is well known. Much, however, remains unknown about the time-dependent behaviour of FRC under sustained loading let alone the mechanism causing the phenomenon. This paper reports a study of the time-dependent behaviour of pre-cracked macro-synthetic fibre reinforced concrete (MSFRC) subjected to uni-axial tensile sustained loading. To fully understand the creep behaviour, investigation of the time-dependent fibre pull-out and fibre creep was also conducted. For the purpose of in-service simulation, the MSFRC specimens were pre-cracked before testing. Stress levels investigated were 30–70% of the residual, post crack, uni-axial tensile strength of the MSFRC. The experimental investigations revealed that cracked MSFRC shows significant creep and the fibre creep and the time-dependent fibre pull-out are the major sources of the creep behaviour.
79 citations
Additional excerpts
... (6)...
[...]
...본 연구에서는 강섬유보강 콘크리트의 90일 간의 휨 크리 프에 대한 영향 및 거동을 확인하기 위해 식 (5) 및 (6) 과 같은 식을 산정하여 활용 하였다....
[...]
TL;DR: In this article, the effect of a number of variables on flexural creep of steel fiber reinforced concrete in its cracked state was assessed, namely fiber geometry (slenderness and length), fiber content, concrete compressive strength, maximum aggregate size, and flexural load.
58 citations
Additional excerpts
...(Arango et al. 2012 & Garcia-Taengua et al. 2014) Fig....
[...]
TL;DR: In this article, a test setup and methodology for testing the flexural creep behaviour of pre-cracked Fibre Reinforced Concrete (FRC) specimens, aimed at providing a basis for standardization, is presented.
Abstract: This paper presents a proposal of test setup and methodology for testing the flexural creep behaviour of pre-cracked Fibre Reinforced Concrete (FRC) specimens, aimed at providing a basis for standardization. The design criteria used to define the equipment and methodology are presented. A test results sheet and a curve are established to present the results of creep tests, and some experimental results are shown so that the test can be validated. The equipment and methodology proposed make it possible to research the influence of factors such as concrete type, fibres type and content, applied load, and crack opening value.
49 citations
Additional excerpts
...fib model code에서 제안하는 식 (3) 및 (4)에서 모두 만족하였는데, 이는 모든 실험체가 혼입률 0....
[...]
...fib model code 2010에서는 EN-14651 휨 성능 평가를 근거 로 하여 식 (3) 및 (4)를 만족하는 경우 강섬유가 인장보강근을 일부 대체하거나 전체를 대체할 수 있다고 제시하고 있다....
[...]