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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 68 Abstracts search results
Document:
24-214
Date:
May 8, 2025
Author(s):
Devid Falliano, Luciana Restuccia, Jean-Marc Tulliani and Giuseppe Andrea Ferro
Publication:
Materials Journal
Abstract:
Biochar properties, in particular, its fineness and its ability to absorb water, can be exploited to modify the rheological behaviour of cementitious conglomerates and to improve the hydration of the cement paste under adverse curing conditions such as those related to 3D concrete printing. Regarding the fresh state properties, the study of the rheological properties conducted on cementitious pastes for different biochar additions (by weight of cement: 0%, 1.5%, 2%, and 3%) highlights that the biochar induces an increase in yield stress and plastic viscosity. The investigation of mechanical properties, in particular flexural sand compressive strength, performed on mortars, evidences the internal curing effect promoted by biochar additions (by weight of cement: 0%, 3%, and 7.7%). In fact, compared to the corresponding specimens cured for the first 48 hours in the formwork, specimens with biochar addition cured directly in air are characterised by a drastically lower reduction in compressive strength than the reference specimens, i.e., approximately 36% and 48% respectively. This interesting result can also be exploited in traditional construction techniques, where faster demolding is needed.
DOI:
10.14359/51746809
23-029
May 1, 2025
H. Kim, Y. Yi, R. A. Boehm, Z. D. Webb, J. Choi, J. Murcia-Delso, T. D. Hrynyk, and O. Bayrak
Structural Journal
Volume:
122
Issue:
3
focused on the impacts of geometric design parameters on the structural performance of drilled shaft footings. Large-scale tests were conducted on specimens subjected to uniform column compression and constructed with different geometric conditions permitting the examination of varied strut inclination, shaft diameter, and footing depth. The experimental results obtained confirmed that footing strength was highly dependent on strut inclination while shaft diameter affected the ultimate damage pattern. Strength calculations based on three-dimensional (3-D) strut-and-tie modeling guidelines recently developed by the authors provided less conservative results as compared to previous recommendations and resulted in levels of accuracy consistent with those of other shear design procedures adopted in code provisions.
10.14359/51745637
23-218
March 1, 2025
Yasuaki Ishikawa, Tomoki Ito, and Satoshi Hayakawa
2
This paper examines the inaccuracy of the initial strain method that is generally adopted in three-dimensional (3-D) finite element prestressing analysis and discusses the merits of a newly developed method to calculate 3-D prestressing effects. The new method considers friction loss of the tendon force as well as pseudo- centripetal forces, allowing a wide range of functional forms for the prestressed concrete (PC) steel force distribution assumption. This study examined the basic concepts for adopting the functional form of the PC steel force distribution at the prestressing and seating stages, after which the observed and calculated values of pulled-out lengths of PC steel were compared to assure the credibility of the assumed functional form of the PC steel force distribution. A three-span continuous bridge model was used to compare results obtained by the conventional method and the new 3-D method. The equilibrium of a free body was used also to evaluate the accuracy of results by the new method. The importance of the new method being able to calculate a pulled-out PC steel length considering concrete deformation was stressed because this value may be adopted to confirm assumptions of the PC steel force distribution.
10.14359/51744393
22-298
September 1, 2024
Junhyung Kim and Raissa Douglas Ferron
121
5
Embedding magnetic particles into cement paste produces a smart material in which the rheological properties of the resultant paste can be actively controlled through the use of magnetorheological (MR) principles. This research investigates the rheological behavior of cement-based MR pastes with and without air entrainment to gain a better understanding of the effects of air-entrained bubbles on MR cement pastes. Such information would be critical for the use of such MR pastes in three-dimensional (3-D) concrete printing applications. It is revealed that the incorporation of entrained air increases the MR response, and this effect is related to the bubble-bridge effect.
10.14359/51742113
23-170
Hiroshi Nishio, Yosuke Yagi, and Yasuaki Ishikawa
A three-dimensional (3-D) finite element method for prestressing and seating analysis has been developed. This method improves the accuracy of the results obtained using the widely adopted initial stress method and enables calculation of the seating loss effect, which is the final stress prediction of prestressing. Its application for large numbers of indeterminate-order structures is shown by comparing its calculation results with two-dimensional (2-D) conventional analysis, as well as with observed strain results for cables of an existing 462 m, six-span continuous bridge. With these considerations, a new management method of prestressing for jack force-diverting systems where the prestressing force does not focus uniquely on a design section was developed so that constructed prestressed concrete structures can be well-secured to comply with design objectives.
10.14359/51740857
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