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International Concrete Abstracts Portal

Showing 1-5 of 304 Abstracts search results

Document: 

SP345

Date: 

February 19, 2021

Author(s):

ACI Committee 549

Publication:

Symposium Papers

Volume:

345

Abstract:

Sponsors: ACI Committee 549, Rilem-MCC Editors: Barzin Mobasher and Flávio de Andrade Silva Several state-of-the-art sessions on textile-reinforced concrete/fabric-reinforced cementitious matrix (TRC/FRCM) were organized by ACI Committee 549 in collaboration with RILEM TC MCC during the ACI Fall 2019 Convention in Cincinnati, OH, and the ACI Virtual Technical Presentations in June 2020. The forum provided a unique opportunity to collect information and present knowledge in the field of TRC and FRCM as sustainable construction materials. The term TRC is typically used for new construction applications whereas the term FRCM refers to the repair applications of existing concrete and masonry. Both methods use a textile mesh as reinforcement and a cementitious-based matrix component and, due to high tensile and flexural strength and ductility, can be used to support structural loads. The technical sessions aimed to promote the technology, and document and develop recommendations for testing, design, and analysis, as well as to showcase the key features of these ductile and strong cement composite systems. New methods for characterization of key parameters were presented, and the results were collected towards the development of technical and state-of-the-art papers. Textile types include polymer-based (low and high stiffness), glass, natural, basalt, carbon, steel, and hybrid, whereas the matrix can include cementitious, geopolymers, and lightweight matrix (aggregates). Additives such as short fibers, fillers, and nanomaterials were also considered. The sessions were attended by researchers, designers, students, and participants from the construction and fiber industries. The presence of people with different expertise and from different regions of the world provided a unique opportunity to share knowledge and promote collaborative efforts. The experience of an online technical forum was a success and may be used for future opportunities. The workshop technical sessions chairs sincerely thank the ACI staff for doing a wonderful job in organizing the virtual sessions and ACI TC 549 and Rilem TC MCC for the collaboration.


Document: 

SP-345_10

Date: 

February 1, 2021

Author(s):

Goezdem Dittel, Kira Heins, Thomas Gries

Publication:

Symposium Papers

Volume:

345

Abstract:

There is a great demand in the world for low-cost and functional pipeline systems due to the renovation requirements of pipes in use and the continuous development of new settlements. Previously used pipeline systems made of steel reinforced concrete are economical and sufficiently resistant. However, due to the corrodibility of steel reinforcement and to enable sufficient crack reduction, large wall thicknesses and thus heavy constructions are required. Textile reinforced concrete (TRC) eliminates these disadvantages by enabling the production of light and thin-walled structures.

The aim of this research is the development of a concept for the realization of smart pipes made of sensory TRC by using the advantages of lightweight, thin-walled structures, focusing on the production process. Based on different warp knitted textile variations with different coating concentrations, preliminary tests were carried out using the fourpoint bending test. As a result of the preliminary tests, the textile variation of counterlaid tricot with a maximum coating concentration was selected as a suitable reinforcing material for the concept development. Concepts for the production of smart TRC pipes are developed accordingly. As a result, a casting mold and process were created which allowed a production with reduced diameter and depth of pores and concentric positioning of the reinforcement structure.


Document: 

SP-340-06

Date: 

April 1, 2020

Author(s):

Maria Kaszynska and Adam Zielinski

Publication:

Symposium Papers

Volume:

340

Abstract:

The research paper presents an analysis of autogenous shrinkage development in self-consolidating concrete (SCC). The first stage of the study involved an evaluation of concrete susceptibility to cracking caused by shrinkage of SCC with natural and lightweight aggregate. The shrinkage was tested on concrete rings according to ASTM C 1581/C 1581M- 09a. The influence of aggregate composition, the water content in lightweight aggregate, and SRA admixture on the reduction of concrete susceptibility to cracking, due to the early-age shrinkage deformation was determined. In the second stage of the research, the innovative method measurement of autogenous shrinkage was developed and implemented. The tests were performed on concrete block samples, dimensions 35x150x1150 mm, that had the same concrete volume as ring specimen in the ASTM method. Linear deformation of the concrete samples was measured in constant periods of 500 s using dial gauges with digital data loggers. The investigation allowed evaluating of the influence of water/cement (w/c) ratio of 0.28, 0.34, 0.42, and of aggregate composition on the development of autogenous shrinkage in different stages of curing SCC. The results were compared to existing material models proposed by other researchers. The conducted study indicated a significant influence of the w/c ratio and composition of aggregate on the concrete susceptibility to crack caused by the autogenous shrinkage deformation.


Document: 

SP-336_01

Date: 

December 11, 2019

Author(s):

James Lafikes, Rouzbeh Khajehdehi, Muzai Feng, Matthew O’Reilly, David Darwin

Publication:

Symposium Papers

Volume:

336

Abstract:

Supplementary cementitious materials (SCMs) in conjunction with pre-wetted fine lightweight aggregate to provide internal curing are being increasingly used to produce high performance, low-shrinking concrete to mitigate bridge deck cracking, providing more sustainable projects with a longer service life. Additionally, the SCMs aid in concrete sustainability by reducing the amount of cement needed in these projects. This study examines the density of cracks in bridge decks in Indiana and Utah that incorporated internal curing with various combinations of portland cement and SCMs, specifically, slag cement, Class C and Class F fly ash, and silica fume, in concrete mixtures with water-cementitious material ratios ranging from 0.39 to 0.44. When compared with crack densities in low-cracking high-performance concrete (LC-HPC) and control bridge decks in Kansas, concrete mixtures with a paste content higher than 27% exhibited more cracking, regardless of the use of internal curing or SCMs. Bridge decks with paste contents below 26% that incorporate internal curing and SCMs exhibited low cracking at early ages, although additional surveys will be needed before conclusions on long term behavior can be made.


Document: 

SP-334-05

Date: 

September 30, 2019

Author(s):

Fariborz M Tehrani, John Carreon, and Nathan Miller

Publication:

Symposium Papers

Volume:

334

Abstract:

Detailed experimental and analytical studies were carried to investigate the effect of recycled tire-derived aggregates (TDA) on ductility and toughness of lightweight aggregate (LWA) concrete specimens containing coarse expanded shale aggregates and fine mineral aggregates. Investigations covered six different concrete mix with various portions of LWA replaced by TDA. Mechanical properties of each mix, including compressive strength, splitting tensile strength, flexural strength, and modulus of elasticity were measured to obtain the optimum range of TDA to LWA ratio. Further, dynamic destructive tests were carried to highlight the performance of tire-derived lightweight aggregate concrete (TDLWAC) subjected to impact loads. Moreover, the post-peak behavior of these specimens was modeled using a linear elastic fracture mechanics relationship. The model successfully demonstrated the effect of TDA in the enhancement of cracking behavior of TDLWAC.


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