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International Concrete Abstracts Portal

Showing 1-5 of 16 Abstracts search results

Document: 

21-493

Date: 

January 1, 2023

Author(s):

M. Selvam and Surender Singh

Publication:

Materials Journal

Volume:

120

Issue:

1

Abstract:

Lack of understanding of the compaction mechanism, both in the laboratory and field, could result in significant underestimation or overestimation of the roller-compacted concrete pavement (RCCP) performance. The literature (1987 to 2022) depicts that there are numerous techniques to design RCCP in the laboratory; however, which method could closely simulate the field compaction is not fully explored. The present paper critically reviews the fundamental parameters affecting the strength characteristics of RCCP when compacted with different compaction mechanisms in the laboratory and attempts to rank the compaction methods based on the field performance. Also, recommendations are made on how to fabricate the specimens without having much impact on the considered compaction technique. The techniques that have been considered are the vibratory hammer, vibratory table, modified Proctor, gyratory compactor, and special compactors such as California kneading compactor, Marshall hammer, and duplex roller. Based on the present review, future research prospects are outlined to improve the performance of RCCP.

DOI:

10.14359/51737290


Document: 

20-219

Date: 

July 1, 2021

Author(s):

R. V. M. Toffolo, T. K. Moro, D. H. Santos, L. C. B. Costa, J. C. Mendes, and R. A. F. Peixoto

Publication:

Materials Journal

Volume:

118

Issue:

4

Abstract:

This work evaluates the technical feasibility of a roller-compacted concrete (RCC) pavement with complete replacement of natural aggregates by electric arc furnace slag (EAFS) or basic oxygen furnace slag (BOFS). The methodology includes, initially, the processing of the slags, and physical, chemical, and environmental characterization of the natural and slag aggregates. Subsequently, concrete mixtures were designed, and the compaction at optimum moisture was performed. Finally, the behavior of specimens under service and their mechanical performance were evaluated. Results show that both EAFS and BOFS enhance the RCC’s compressive strength and modulus of elasticity. The RCC produced with BOFS aggregates presented some expansibility due to its high contents of chemically active finer-than-75-µm materials and higher porosity. The EAFS aggregate was stable in durability analysis. In conclusion, through optimal mixture proportions and using compatible energy compression, it is viable to produce pavements with EAFS steelmaking slag in efficient, economical, and environmentally friendly manners. BOFS also showed promising results but requires further investigation.

DOI:

10.14359/51732791


Document: 

19-477

Date: 

January 1, 2021

Author(s):

Solomon Debbarma and G. D. Ransinchung R. N.

Publication:

Materials Journal

Volume:

118

Issue:

1

Abstract:

The paper aims to address the use of natrojarosite, an industrial waste material, as a partial replacement to portland cement in roller-compacted concrete pavement (RCCP) mixtures. Natrojarosite particles were used in proportions of 0%, 5%, 15%, 20%, and 25%, by weight of cement, respectively. It was observed that the optimum moisture content increases as the natrojarosite replacement level increases but were still lower than that of the control mixture. Meanwhile, the maximum dry density was found to be enhanced until 15% of natrojarosite replacement level, and subsequently, the strength and transport properties were also found to be improved. Scanning electron microscope images confirmed that the natrojarosite particles acted as a filler material which improved the transition zone and pore structure of the hydrated matrix. Contrarily, higher replacement levels showed reduction in the concrete strength and higher susceptibility to acid attack primarily due to the high sulfur trioxide content in the natrojarosite particles. Nevertheless, natrojarosite of up to 15% could be used to improve the strength and durability of RCCP. Moreover, the use of natrojarosite particles would lower the consumption of portland cement and eliminate the disposal issue of the harmful natrojarosite waste.

DOI:

10.14359/51728281


Document: 

17-194

Date: 

March 1, 2018

Author(s):

George J. Zimmer, Robert Flynn, Eric Musselman, and Jeremy Young

Publication:

Materials Journal

Volume:

115

Issue:

2

Abstract:

Roller-compacted concrete (RCC) is often used to construct hydraulic structures, and in gravity dam applications, a facing system is required to control seepage along lift lines. One facing system that is gaining popularity is grout-enriched RCC (GERCC). This innovative process requires the addition of a neat cement grout to the uncompacted RCC along the face, followed by internal vibration to combine the material. One limitation of GERCC is previous research has shown difficulty in entraining air in this system. This study optimized the grout formulation to develop a stable air void system, and then evaluated the effect of this grout on the freezing-and-thawing resistance of GERCC produced both in the lab and during a field trial. Additionally, various grout placement techniques, grout dosages, and vibration levels were evaluated. The results show that freezing-and-thawing-resistant GERCC can be created when the grout and RCC are thoroughly combined.

DOI:

10.14359/51701236


Document: 

15-190

Date: 

July 1, 2017

Author(s):

Ziyad Majeed Abed and Abeer Abdulqader Salih

Publication:

Materials Journal

Volume:

114

Issue:

4

Abstract:

Roller-compacted concrete (RCC) is concrete that has no slump, no forms, no reinforcing steel, no finishing, and is wet enough to support compaction by vibratory rollers. Due to the effectiveness of curing on properties and durability, the essential aim of this research is to study the effect of various curing methods (air curing, 7 days of water curing, emulsified asphalt curing, and permanent water curing) and porcelanite (lightweight aggregate used as an internal curing agent) with different replacement percentages of fine aggregate (volumetric replacement) on RCC and to explore the possibility of introducing practical RCC for road pavement with a minimum requirement of curing. Specimens were sawed from slabs of 14.96 x 14.96 x 3.94 in. (380 x 380 x 100 mm). Results show that using 5% porcelanite improved RCC (with air curing) as compared to reference RCC (with permanent water curing) by percentages ranging from 0.4 to 1.7, 3.6 to 28.9, and 15.9 to –41.3% for bulk density, flexural strength, and water absorption, respectively

DOI:

10.14359/51689775


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