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Home > Publications > International Concrete Abstracts Portal
Showing 1-5 of 8 Abstracts search results
Document:
21-452
Date:
January 1, 2023
Author(s):
Alessandro P. Fantilli and Tomoya Nishiwaki
Publication:
Materials Journal
Volume:
120
Issue:
1
Abstract:
An experimental campaign, performed on different types of ultra-high-performance fiber-reinforced cementitious composite (UHP-FRCC)—made with four replacement rates (0, 20, 50, and 70%) of cement with fly ash and cured for 1, 4, and 13 weeks—is described in this paper. Specifically, 72 cylinders were tested to measure the compressive strength and Young’s modulus of elasticity; stress-strain relationships were obtained from 72 dumbbell-type specimens subjected to uniaxial tension, and 12 beams, tested in four-point bending, provided the moment-curvature diagrams. The best UHP-FRCC was selected through an eco-mechanical analysis, capable of combining the mechanical performance with the environmental impact of concrete. When the ultimate bending moment of a beam is the functional unit of this analysis, the higher the replacement rate of cement, the better the beam performance, although material properties and structural ductility show opposite trends.
DOI:
10.14359/51737330
21-161
March 1, 2022
Alessandro P. Fantilli and Farmehr M. Dehkordi
119
2
Experimental research performed on fiber-reinforced cement-based composites made with polymeric aggregate and reinforced with recycled steel fibers is presented in this paper. In total, 18 concrete prisms were cast with a two-stage procedure: first, the fibers from end-of-life tires were put in the molds and, subsequently, they were covered by a cementitious grout containing fine (recycled or virgin) aggregate. The two-stage composites showed more than one crack and a deflection-hardening behavior in the post-cracking regime by performing three-point bending tests. Moreover, both flexural and compressive strength increased with the fiber volume fraction. Thus, if the content of recycled materials is suitably selected, the ecological and mechanical performances of the two-stage composites improve and become similar to those of one-stage fiber-reinforced concrete made with only virgin components.
10.14359/51734300
18-289
July 1, 2019
Nancy Beuntner, Ricarda Sposito, and Karl-Christian Thienel
116
4
Calcined clays have become increasingly attractive as supplementary cementitious materials (SCMs). This paper begins with describing the mineralogical diversity of clays and presents the advantages of naturally occurring mixed-layer clays. It illustrates the necessity of optimal calcination temperatures depending on type of clay, and first steps are discussed toward industrial production. The following chapter gives an overview of selected physical and chemical-mineralogical properties and the essential reaction mechanisms of calcined clays as SCMs. The latest findings on their influence on early hydration and their special role in fresh concrete are presented. The potential of calcined clays in concrete is highlighted exemplary for selected mechanical properties and durability aspects. Lastly, the potential and limits of calcined clays as a future part of blended cements or concrete additive are evaluated, considering ecological aspects, as well.
10.14359/51716677
16-238
January 1, 2018
Hasan Sahan Arel and Ertug Aydin
115
This work investigated the effects of Class F fly ash (FA), coconut husk ash (CHA), and rice husk ash (RHA) as cement replacements at various proportions on the workability, setting time, compressive strength, and pullout strength of concrete. Concretes containing partial replacement of cement by 20 and 40% FA and 10, 15, and 20% CHA and RHA were investigated. The results revealed that FA, CHA, and RHA can be used as replacements for cement in concrete production to produce sustainable and ecological products. The mixed composition of 20% FA and 20% RHA had 15.3% greater compressive strength than that of the reference composition after 180 days, while a slight reduction in this parameter was observed in FA-CHA combinations. FA and RHA mixtures showed the highest compressive and pullout strengths for all aging times tested.
10.14359/51700991
16-350
September 1, 2017
Zhiyong Liu, Weiwei Chen, Wenhua Zhang, Yunsheng Zhang, and Henglin Lv
114
5
An ecological ultra-high-performance cementitious composite (ECO-UHPCC) was investigated in this paper. The ECO-UHPCC has three characteristics: low cement content (400 to 520 kg/m3 [24.97 to 32.46 lb/ft3]), contains nature river sand and high strength coarse aggregate, and is cured in standard condition. The complete stress-strain behavior of ECO-UHPCC under uniaxial compression was systematically investigated. First, a series of ECO-UHPCC specimens containing different coarse aggregates and steel fibers were fabricated. Second, the uniaxial compressive tests were conducted by a high-stiffness, closed-loop, servocontrolled, material testing machine, and the complete stressstrain curves of ECO-UHPCC were obtained. Then, the results, including complete stress-strain behavior, compressive strength, elastic modulus, Poisson’s ratio, toughness, and fracture pattern of ECO-UHPCC were systematically analyzed. The test results show that ECO-UHPCC exhibits better compressive strength and stiffness than high-performance concrete. The compressive strength and elastic modulus of ECO-UHPCC with basalt coarse aggregate and 2% steel fiber were up to 128.4 MPa (18.62 ksi) and 46.2 GPa (6700.51 ksi), respectively. Finally, a new model was developed for predicting the complete stress-strain behavior of ECO-UHPCC under uniaxial compression. This model shows a good correlation with the experimental results.
10.14359/51689899
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