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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-5 of 381 Abstracts search results
Document:
23-322
Date:
March 1, 2025
Author(s):
Yail J. Kim, Jun Wang, Woo-Tai Jung, Jae-Yoon Kang, and Jong-Sup Park
Publication:
Structural Journal
Volume:
122
Issue:
2
Abstract:
This paper presents the implications of creep-fatigue interactions for the long-term behavior of bulb-tee bridge girders prestressed with either steel strands or carbon fiber-reinforced polymer (CFRP) tendons. A large amount of weigh-in-motion data incorporating 194 million vehicles are classified to realistically represent live loads. Computational simulations are conducted as per the engagement of discrete autonomous entities in line with time- dependent material models. In general, the properties of CFRP tendons vary insignificantly over 100 years; however, the stress range of CFRP responds to fatigue cycles. Regarding prestress losses, the conventional method with initial material properties renders conservative predictions relative to refined approaches considering time-varying properties. The creep and fatigue effects alter the post-yield and post-cracking responses of steel- and CFRP-prestressed girders, respectively. From deformational capability standpoints, steel-prestressed girders are more vulnerable to fatigue in comparison with CFRP-prestressed ones. It is recommended that the fatigue truck and the compression limit of published specifications be updated to accommodate the ramifications of contemporary traffic loadings. Although the operational reliability of both girder types is satisfactory, CFRP-prestressed girders outperform their steel counterparts in terms of fatigue safety. Technical findings are integrated to propose design recommendations.
DOI:
10.14359/51743304
21-069
July 1, 2024
Callum Harper and Shamim A. Sheikh
121
4
This paper presents the results of creep rupture tests conducted ontwo different sizes of glass fiber-reinforced polymer (GFRP) bars from two different manufacturers under high alkaline conditions at room temperature (approximately 23 and 60°C [73.4 and 140°F]).Regular tensile tests were also conducted on the bars at the two temperatures to provide insight into the effects of high temperatureon their long-term performance. The results show that the larger bar performed slightly better at room temperature but significantly better at the elevated temperature. The larger-sized bars also lost less tensile strength at the elevated temperature. It was observed that temperature had a greater effect on the long-term performance of GFRP bars than alkalinity. The current design code limits on the allowable stresses were evaluated against the test results and found to be overly conservative.
10.14359/51740708
22-276
May 1, 2024
Chuyuan Wen, Dejian Shen, Yang Jiao, Ci Liu, and Ming Li
3
High-strength concrete (HSC) with a low water-cement ratio (w/c) may experience large autogenous shrinkage (AS). When shrinkage of concrete is restrained by the subgrade, foundation, or other part of the structure, HSC is more prone to crack. However, studies devoted to the early-age cracking resistance of reinforced HSC under uniaxial restrained conditions and adiabatic conditions are still lacking. In the current research, the effect of reinforcement percentage and reinforcement configuration on the temperature history, shrinkage, stress, and creep behavior of reinforced HSC at early age was analyzed using the temperature-stress test machine. Test results showed that reinforcement could effectively restrain the development of concrete shrinkage and creep. The cracking resistance of HSC increased with increasing reinforcement percentage, evaluated by the integrated criterion. With the same reinforcement percentage, reinforced HSC with distributed reinforcement along with a proper thickness of concrete cover exhibited higher cracking resistance compared with that of central reinforcement.
10.14359/51740456
22-200
September 1, 2023
S. Fernando, C. Gunasekara, D. W. Law, M. C. M. Nasvi, S. Setunge, and R. Dissanayake
Materials Journal
120
5
The creep and drying shrinkage of two alkali-activated concretes produced with low-calcium fly ash and rice husk ash (RHA) were investigated over a period of 1 year. The compressive strength of 100% low-calcium fly ash (100NFA) concrete and the concrete having 10% RHA replacement (10RHA) decreased from 49.8 to 37.7 MPa (7.22 to 5.47 ksi) and 30.2 to 18.3 MPa (4.38 to 2.65 ksi), respectively, between 28 and 365 days. The imbalance in the dissolution rate of the raw materials in the blended system (10RHA) could negatively influence the strength properties, which leads to poor matrix integrity and a highly porous structure when compared with 100NFA. The presence of the micro-aggregates due to the block polymerization provides the effect of increasing the aggregate content in the 100NFA concrete compared with the 10RHA concrete, which is hypothesized as one of the reasons creep and shrinkage properties deteriorated in 10RHA.
10.14359/51738891
22-242
May 1, 2023
Brock D. Hedegaard, Timothy J. Clement, and Mija H. Hubler
A new semi-empirical concrete shrinkage and creep model called the CPRH Model is proposed and calibrated. The new model proposes a coupling between autogenous and drying shrinkage using a volume-average pore relative humidity and treats drying creep as an additional stress-dependent shrinkage, linking together all these phenomena. The proposed expressions are designed to facilitate traditional integral-type analysis, but also uniquely support ratetype calculations that can be leveraged by analysis software. Model calibration uses the Northwestern University (NU) database of creep and shrinkage tests to determine new model parameters. The proposed model uses minimal inputs that are often known or may be assumed by the design engineer. Comparison of the proposed model to historical time-dependent models indicates that the new model provides a superior fit over a wider range of inputs.
10.14359/51738709
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