ABOUT THE 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.

International Concrete Abstracts Portal

Showing 1-5 of 7 Abstracts search results

Document: 

19-035

Date: 

January 1, 2020

Author(s):

Aravind Tankasala and Anton K. Schindler

Publication:

Materials Journal

Volume:

117

Issue:

1

Abstract:

In this project, the effect of using lightweight aggregate (expanded slate) on the early-age cracking tendency of mass concrete mixtures was evaluated. Concretes representative of mass concrete mixtures—namely, normal-weight concrete, internally cured concrete, sand-lightweight concrete, and all-lightweight concrete—at two different water-cementitious materials ratios (0.38 and 0.45) were tested in cracking frames from the time of setting until the onset of cracking. The development of early-age concrete stresses caused by autogenous and thermal shrinkage effects were measured from setting to cracking. The behavior of concretes containing lightweight aggregates was compared with normal-weight concrete placed under temperature conditions simulating fall placement in mass concrete applications. Increasing the amount of pre-wetted lightweight aggregates in concrete results in systematic decrease in density, reduced modulus of elasticity, and reduced coefficient of thermal expansion. All these factors effectively improve the concrete’s early-age cracking resistance in mass concrete applications.

DOI:

10.14359/51719082


Document: 

18-481

Date: 

November 1, 2019

Author(s):

Augustine Uchechukwu Elinwa and Nasir Kabir

Publication:

Materials Journal

Volume:

116

Issue:

6

Abstract:

This research work was on the evaluation of the flexural strength and compressive strength relationship of spent foundry sand (SFS) concrete. The relationship was established using a concrete mixture of 1:1.71:2.56, a cement content of 404 kg/m2, and a water-cement ratio (w/c) of 0.52. This was used to cast beams of dimensions 150 x 150 x 500 mm (6 x 6 x 20 in.) cured for 90 days in a water curing tank under laboratory conditions. The SFS was used to replace fine aggregate (FA) 0 to 40% by wt. The evaluations on the statistical characteristics of the flexural strength data results showed that the addition of SFS to concrete improved the hydration process. This was reflected in the strength development of the concrete and the strong correlation and level of significance observed with the variables (mixture and age). The values of the modulus of rupture (MOR) obtained are in the range of 4.6 to 6.6 MPa; this was at the optimum replacement of 10%. At this level, the value of the flexural strength was approximately 29% of the compressive strength. The two models chosen that represented the flexural strength and compressive strength relations are the square root and 2/3 models. The relative predictive error (RPE) for each is 0.1 and 0.2, respectively.

DOI:

10.14359/51718055


Document: 

104-M33

Date: 

May 1, 2007

Author(s):

Neven Krstulovic-Opara

Publication:

Materials Journal

Volume:

104

Issue:

3

Abstract:

Significant interest has been generated in recent years in the development, design, and construction of liquefied gas containment tanks, such as liquefied natural gas (LNG) tanks. Consequently, a large number of LNG tanks are planned for construction in the near future. Concrete is particularly well suited for construction of such tanks. Its properties and behavior at cryogenic temperatures (for example, –160 °C [–260 °F]), however, differs significantly from known behavior at room temperatures. This paper presents the effect of cryogenic temperatures on the stress-strain response, compression strength, tension strength, flexural strength, Young’s modulus, Poisson’s ratio, coefficient of thermal expansion, thermal conductivity, creep, and permeability. Available data indicate that concrete properties improve at cryogenic temperatures. The extent of improvement is highly dependent on moisture content.

DOI:

10.14359/18676


Document: 

89-M21

Date: 

March 1, 1992

Author(s):

Nicholas J. Carino and Rajesh C. Tank

Publication:

Materials Journal

Volume:

89

Issue:

2

Abstract:

The "rate constant model" is proposed for estimating relative strength gain of concrete under different isothermal curing conditions. The key feature of the model is the relationship between curing temperature and the rate constant for relative strength development. The strength-versus-age relationships of seven concrete and mortar mixtures under three curing temperatures were studied. The rate constants were determined by using an hyperbolic strength-age function. It was found that a simple exponential function described the observed variations of the rate constant with curing temperature. It is shown that the relative strength development of concrete can be estimated from its temperature history using parameters determined experimentally from tests of isothermally cured mortar specimens.

DOI:

10.14359/2275


Document: 

88-M11

Date: 

January 1, 1991

Author(s):

Rajesh C. Tank and Nicholas J. Carino

Publication:

Materials Journal

Volume:

88

Issue:

1

Abstract:

The rate constant for strength development of a particular concrete mixture is the initial slope of the relative strength-versus-age curve at constant temperature curing. The form of the rate constant-versus-temperature function is needed to describe the combined effects of time and temperature on strength development. This study investigates the relationship between the rate constant and curing temperature. Based on strength-gain data for concrete and mortar specimens made with Type I cement and cured at 10, 23, and 40 C (50, 73, and 104 F), the following conclusions are drawn: 1) strength gain can be represented by a three-parameter hyperbolic function; 2) the rate constant is a nonlinear function of curing temperature, and a simple exponential function describes this relationship; 3) tests of appropriate mortar specimens provide the information needed to predict relative strength development of the corresponding concrete; and 4) the proposed rate constant model accurately describes the development of relative strength as a function of the equivalent age.

DOI:

10.14359/2403


12

Results Per Page 




Please enter this 5 digit unlock code on the web page.