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International Concrete Abstracts Portal

Showing 1-5 of 62 Abstracts search results

Document: 

18-417

Date: 

May 1, 2020

Author(s):

Kamran Amini, Kristen Cetin, Halil Ceylan, and Peter C. Taylor

Publication:

Materials Journal

Volume:

117

Issue:

3

Abstract:

This paper compiles results from three different laboratory studies and employs multivariate regression analyses to model the effect of mixture parameters and concrete hardened properties on saltscaling performance. The correlations between concrete hardened properties and mixture proportions were also studied. The modeled mixture parameters included water-cementitious materials ratio (w/cm), slag cement, and air content. Concrete performance was evaluated through abrasion resistance, sorptivity, compressive strength, and salt scaling tests. According to the results obtained in this study, concrete scaling performance is affected, in the order of importance, by w/cm, slag-cement replacement, and air content. In addition, concrete hardened properties, especially abrasion resistance, were found useful in making reliable salt-scaling predictions. Based on the results derived from the regression analyses and the discussions provided in the reviewed literature, recommendations are given for proportioning of concrete to obtain adequate performance with respect to compressive strength, abrasion resistance, sorptivity, and salt-scaling resistance. In addition, the relationship between concrete properties, ingredients, and effective mechanisms are investigated.

DOI:

10.14359/51724614


Document: 

19-022

Date: 

January 1, 2020

Author(s):

A. S. Carey, I. L. Howard, D. A. Scott, R. D. Moser, J. Shannon, and A. Knizley

Publication:

Materials Journal

Volume:

117

Issue:

1

Abstract:

This paper evaluated constituent proportions on mechanical and thermal properties of ultra-high-performance concrete. This paper assessed how fine aggregates and fibers at varying proportions enhance cement paste and can improve its mechanical properties to a desired compressive strength, elastic modulus, or tensile strength. Approximately 400 specimens were tested for mechanical properties within four curing regimes and 22 different mixtures. These experiments aimed to add to the body of knowledge found during literature review. Past efforts found in literature have drawn conclusions by varying one ingredient at a time, whereas the current effort systematically varied multiple ingredients. Results showed compressive strength to be due to synergistic relationships between cement paste, fine aggregates, and steel fibers where absence of any ingredient reduced strength. Tensile strength and elastic modulus were dominated by a single ingredient.

DOI:

10.14359/51719076


Document: 

18-224

Date: 

March 1, 2019

Author(s):

Kamran Amini, Seyedhamed Sadati, Halil Ceylan, and Peter C. Taylor

Publication:

Materials Journal

Volume:

116

Issue:

2

Abstract:

With adoption of winter maintenance strategies that typically include incorporation of aggressive deicer chemicals, pavement surfaces in cold regions are exposed to the risk of scaling damage. Reduced ride quality due to surface deterioration can eventually lead into a variety of maintenance and repair programs. Such pavement preservation programs impose significant charges to the owner agencies, while raising concerns regarding the safety issues associated with work zone areas. The present study addresses the correlation between surface hardness and concrete hardened properties. Moreover, factors that influence the concrete performance with respect to surface-abrasion resistance (hardness) were investigated. Of special interest was the relationship between surface hardness and concrete salt-scaling performance. An extensive investigation was carried out to assess the effects of various mixture proportions, curing regimes, and finishing times on surface hardness of the concrete specimens. In addition, compressive strength, depth-sensing indentation (DSI), and salt scaling tests were used to evaluate the correlation between concrete surface hardness and performance. A scaling quality classification table using abrasion mass loss values was developed. The results reflect further understanding of the relationship between abrasion resistance and salt scaling resistance that can cause defects when more than two cycles of abrasion testing are applied.

DOI:

10.14359/51714457


Document: 

17-442

Date: 

September 1, 2018

Author(s):

Xuhao Wang, Peter Taylor, Ezgi Yurdakul, and Xin Wang

Publication:

Materials Journal

Volume:

115

Issue:

5

Abstract:

Slipform paving is a road construction process where concrete is extruded by a paver that forms the stiff, fresh concrete into the desired slab shape. Slipform paving is especially suitable for time-sensitive projects requiring high productivity, as it allows placement of 65 to 100 m3 (85 to 130 yds) of concrete per hour. Mixture proportioning for slipform paving applications has often been based on recipes or previous mixtures rather than based on developing proportions for the specific needs of the project using local material. Therefore, a performance-based mixture proportioning approach is needed to balance the target performance requirements for workability, strength, durability, and cost effectiveness for a given project specification. The aim of this study was to develop an innovative performance based mixture proportioning method by analyzing the relationships between the selected mixture characteristics and their corresponding effects on concrete performance. The proposed method provides step-by-step instructions to guide the selection of required aggregate and paste systems based on the performance requirements of slipform pavements.

DOI:

10.14359/51702351


Document: 

17-099

Date: 

January 1, 2018

Author(s):

Weina Meng, V. A. Samaranayake, and Kamal H. Khayat

Publication:

Materials Journal

Volume:

115

Issue:

1

Abstract:

In this study, lightweight sand is used as an internal curing agent in ultra-high-performance concrete (UHPC). A factorial design approach was employed to evaluate the effects of multiple mixture proportioning parameters that are important for mixture optimization of UHPC. The investigated mixture design parameters included the substitution volume ratio of lightweight sand for river sand (LWS/NS: 0 to 25%), the cementitious materials-to-sand volume ratio (cm/s: 0.8 to 1.2), and the water-cementitious materials ratio (w/cm: 0.17 to 0.23). The evaluated properties included fresh properties, compressive strengths at up to 91 days, and autogenous shrinkage at up to 28 days. Statistical models that take into account the coupling effects of mixture proportioning parameters were formulated to predict the UHPC properties. The w/cm and LWS/NS were the most significant parameters influencing the compressive strength and autogenous shrinkage, respectively. By replacing the river sand with 25% lightweight sand, the compressive strength at 91 days increased from 150 to 170 MPa (22.5 to 25.5 ksi) and the autogenous shrinkage at 28 days decreased from 410 to 70 μm/m (410 × 10–6 to 70 × 10–6 in./in.). The mixture with w/cm of 0.23, LWS/NS of 0.25, and cm/s of 1.2 is determined as the optimum UHPC mixture. The material properties of the mixture: the HRWR demand was 0.6%, the 28-day autogenous shrinkage was 260 μm/m (260 × 10–6 in./in.), and the 91-day compressive strength was 147 MPa (22.1 ksi).

DOI:

10.14359/51700995


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