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International Concrete Abstracts Portal

Showing 1-5 of 32 Abstracts search results

Document: 

23-204

Date: 

January 1, 2024

Author(s):

Diala Basim Al-Haddad, Gul Ahmed Jokhio, and Abid Abu-Tair

Publication:

Materials Journal

Volume:

121

Issue:

1

Abstract:

Several incidents of early deterioration of structures have been reported in literature; such incidents have a negative impact. Insufficiencies in the durability design may result from a possible absence of explicit guidelines in design codes and standards that establish a standardized language for building design, construction, and operation. Most design codes and standards, while providing a robust framework for structural capacity and serviceability, do not address durability design to a desirable degree. This study examines and critically reviews the durability design in three international codes: the American, British, and Eurocodes. The study revealed that the European and British standards have comparatively more precise and comprehensive durability provisions, whereas the American code has a larger scope for development. The study introduces a proposal for the improvement of durability design provisions in codes to provide beneficial examples that can assist in the update of upcoming editions of these codes.

DOI:

10.14359/51739154


Document: 

21-106

Date: 

March 1, 2022

Author(s):

Ahmed T. Omar and Assem A. A. Hassan

Publication:

Materials Journal

Volume:

119

Issue:

2

Abstract:

This paper investigates the structural performance of large-scale lightweight self-consolidating concrete (LWSCC) and lightweight vibrated concrete (LWVC) beams made with expanded slate coarse aggregates (ESCAs) and expanded slate fine aggregates (ESFAs) under flexural loads. Nine large-scale concrete beams were cast with different types of lightweight aggregate (either ESCA or ESFA), coarse-to-fine aggregate ratios (0.5 to 1.5), and total binder contents (550 and 600 kg/m3 [34.3 and 37.5 lb/ft3]). The structural performance of the tested beams was assessed based on the characteristics of the load-deflection response, cracking pattern, displacement ductility, energy absorption, cracking moment, and ultimate flexural strength. The reliability of code-based expressions in predicting the cracking and ultimate moment capacity of the tested beams was also investigated in this study. The results indicated that using ESFA better improved the beam’s cracking moment capacity, deformability, ductility, and energy absorption capacity compared to using ESCA. Although LWSCC exhibited a lower modulus of elasticity than normal-weight SCC, the deflection values observed in the LWSCC beams under service loads were well within the allowable limit provided by BS 8110. The measured crack widths at the service loads for all tested beams ranged from 0.20 to 0.26 mm (0.008 to 0.01 in.), satisfying the limits proposed by ACI 318, CSA A23.3, and BS 8110 design codes for durability aspects.

DOI:

10.14359/51734200


Document: 

20-435

Date: 

March 1, 2022

Author(s):

K. S. T. Chopperla, S. Smith, T. Drimalas, N. P. Vaddey, A. Bentivegna, K. E. Kurtis, M. D. A. Thomas, and J. H. Ideker

Publication:

Materials Journal

Volume:

119

Issue:

2

Abstract:

The American Concrete Institute (ACI) provides guides, specifications, and code documents related to concrete durability. The authors reviewed two code documents from ACI Committees 318 and 350, two guidance documents from ACI Committees 201 and 222, and a specification document from ACI Committee 350, and observed that several discrepancies exist in terms of providing uniform durability requirements for freezing and thawing and chemical sulfate attack of concrete, and allowable chloride limits for new construction. By analyzing existing concrete durability data from published literature, laboratory testing, and field exposure sites, recommendations on unified durability requirements and exposure class descriptions are made for potential adoption by ACI Committees 201, 222, 318, and 350.

DOI:

10.14359/51734352


Document: 

20-488

Date: 

September 1, 2021

Author(s):

Bradley S. Hansen, Ashley S. Carey, and Isaac L. Howard

Publication:

Materials Journal

Volume:

118

Issue:

5

Abstract:

Aggregate mineralogy and shape effects on concrete mechanical property relationships were evaluated using 114 concrete mixtures that used rounded gravel, crushed gravel, and limestone. Mineralogy (that is, chert versus calcium carbonate) and shape (that is, crushed versus rounded) were found to have a meaningful effect on the relationships between compressive strength (fc), elastic modulus (E), and splitting tensile strength (St). These data sets were used to benchmark several empirical relationships found in the literature to determine their ability to predict E and St based on fc. Most equations from the literature were conservative and did not consider aggregate type. A set of equations, following the form of ACI 318 and a power equation, are recommended by the authors for limestone, crushed gravel, and rounded gravel to realistically predict E and St based on fc.

DOI:

10.14359/51732933


Document: 

19-444

Date: 

May 1, 2021

Author(s):

Saman Hedjazi and Daniel Castillo

Publication:

Materials Journal

Volume:

118

Issue:

3

Abstract:

This paper determines the effect of steel, glass, and nylon fibers on the elastic modulus of concrete. The effect of different fiber volume fractions (0.1, 0.25, 0.5, 0.75, 1, and 1.5% vol.) and water-cement ratios (w/c: 0.32 to 0.6) on the elastic properties of concrete was investigated using the fundamental resonant frequencies. Experiments were carried out on more than 100 standard cylindrical specimens. The experimental values were determined using resonance frequencies and compared to the available empirical equations in the literature and those of ACI 318 and ACI 363. The dynamic elastic modulus of concrete in the longitudinal and transverse directions were determined experimentally using the resonance test gauge (RTG). Moreover, the dynamic modulus of rigidity of concrete was also determined using the RTG. The results show that the modulus of elasticity of fiber-reinforced concrete (FRC) with a coarse-to-fine aggregate ratio (C/S) less than 1 decreases with the addition of fibers. A new equation to better evaluate the elastic modulus of FRC within the range of 0.1 to 1.5% of fiber volume fraction is proposed. The proposed equation shows good agreement with experimental results.

DOI:

10.14359/51730420


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