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  • 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.

International Concrete Abstracts Portal

Showing 1-5 of 344 Abstracts search results

Document: 

21-029

Date: 

September 1, 2021

Author(s):

Camila Simonetti, Bernardo Fonseca Tutikian, and Luiz Carlos Pinto da Silva Filho

Publication:

Materials Journal

Volume:

118

Issue:

5

Abstract:

The possibility of incorporating scrap tire residue into concrete has already been consolidated in previous studies, but there is a knowledge gap about how concrete made with recycled tire materials behaves when exposed to high temperatures. This study aims to investigate the performance of precast concrete panels made with scrap tire residues when exposed to fire when using recycled steel fiber and recycled rubber aggregates separately. The experimental design consisted of fire resistance tests. Real-scale panels were exposed to the standard fire curve based on ISO 834, measuring the temperatures on the panel surfaces. The recycled steel fiber-reinforced concrete and those containing 5% recycled rubber aggregate presented similar behavior when compared to the conventional concrete on thermal insulation, integrity, and structural stability. The concrete made with 10% recycled rubber aggregate registered the occurrence of explosive spalling and worse thermal insulation and integrity.

DOI:

10.14359/51732983


Document: 

20-443

Date: 

September 1, 2021

Author(s):

Julian Carrillo, José A. Ortiz-Lozano, and Juan G. Rueda-Bayona

Publication:

Materials Journal

Volume:

118

Issue:

5

Abstract:

The evaluation of the mechanical properties of steel fiber-reinforced concrete (SFRC) with different types of fibers and dosages endorses new design recommendations for using several types of construction materials for structural elements. The double-punch test (DPT) offers procedural and economic advantages for evaluating the indirect tensile strength of the SFRC. The objective of this paper is to show and discuss the results of the mechanical characterization obtained experimentally for SFRC using the DPT, with different types of anchorage and fiber dosages. The variables of the study were the dosage of steel fibers (20, 40, and 60 kg/m3) and the number of hooks at the ends of the fiber (1, 1.5, and 2 hooks). The paper develops empirical models for predicting the tensile strength, residual strength, and toughness of SFRC subjected to the DPT without resorting to experimental tests. The models were developed considering the trends of 385 results: 108 from 40 DPTs measured in this study, and 277 from 23 DPTs available in the literature.

DOI:

10.14359/51732932


Document: 

20-400

Date: 

September 1, 2021

Author(s):

S. Gamze Erzengin and Gulce Senturk Guzey

Publication:

Materials Journal

Volume:

118

Issue:

5

Abstract:

Cross-linked polycarboxylates were synthesized and characterized with Fourier-transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), and thermogravimetric analysis (TGA). A comparative investigation of the mechanism behind the relationship between the molecular structure and performance (in terms of rheology, workability retention, and compressive strength) is the novelty of this research. Presence of cross-linkages in polymer structure provided high workability and workability retaining ability to cement pastes. A moderate cross-link density was determined as an important factor for cement dispersion (cross-link/side chain/main chain units molar ratios are 0.2/0.8/10). On the other hand, compressive strengths of designed concretes were significantly affected from the structure of superplasticizers— namely, highly cross-linked polymer provided better compressive strength (73.5 MPa and 72.5% strength increment to the basis of plain concrete). Finally, it was thought that cross-linked polycarboxylate-type superplasticizers could be the functional alternatives of their traditional counterparts, especially for the applications which required more workability and workability retention.

DOI:

10.14359/51732931


Document: 

20-317

Date: 

July 1, 2021

Author(s):

Ankur Bhogayata, Sneh Kakadiya, and Rinkesh Makwana

Publication:

Materials Journal

Volume:

118

Issue:

4

Abstract:

The paper discusses the development and application of the artificial neural network (ANN) model for predicting the compressive and splitting tensile strength of the geopolymer-based concrete composites (GPC). The strength properties of GPC are influenced by the proportions of the constituents—namely, the alkaline solution, fly ash, aggregates, and sand and water—and require optimization for the desired quality of the composite. The optimum mixture may be obtained by using modern techniques; namely ANN modeling. The ANN models have been developed by training and validating the input data using the sigmoid function and the feed-forward backpropagation algorithm in the hidden layers. The ANN layer is the functional part of the model consisting of the operators to carry out the specific task largely based on mathematical calculations. A five-layered ANN model has been developed and used to predict the strength to optimize the mixture design. The predicted values have been compared with the experimental strength values, and the effects of the most significant constituents have been studied.

DOI:

10.14359/51732711


Document: 

20-210

Date: 

July 1, 2021

Author(s):

Tayseer Z. Batran, Mohamed K. Ismail, and Assem A. A. Hassan

Publication:

Materials Journal

Volume:

118

Issue:

4

Abstract:

This study investigated the structural behavior of lightweight self-consolidating concrete (LWSCC) beams strengthened with engineered cementitious composite (ECC). Four LWSCC beams were strengthened at either the compression or tension zone using two types of ECC developed with polyvinyl alcohol (PVA) fibers or steel fibers (SFs). Three beams were also cast in full depth with LWSCC, ECC with PVA, and ECC with SFs, for comparison. The performance of all tested beams was evaluated based on loaddeflection response, cracking behavior, failure mode, first crack load, ultimate load, ductility, and energy absorption capacity. The flexural ultimate capacity of the tested beams was also estimated theoretically and compared to the experimental results. The results indicated that adding the ECC layer at the compression zone of the beam helped the LWSCC beams to sustain a higher ultimate loading, accompanied with obvious increases in the ductility and energy absorption capacity. Higher increases in the flexural capacity were exhibited by the beams strengthened with the ECC layer at the tension zone. Placing the ECC layer at the tension zone also contributed to controlling the formation of cracks, ensuring better durability for structural members. Using ECC with SFs yielded higher flexural capacity in beams compared to using ECC with PVA fibers. The study also indicated that the flexural capacity of single-layer and/or hybrid composite beams was conservatively estimated by the ACI ultimate strength design method and the Henager and Doherty model. More improvements in the Henager and Doherty model’s estimates were observed when the tensile stress of fibrous concrete was obtained experimentally.

DOI:

10.14359/51732635


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