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International Concrete Abstracts Portal

Showing 1-5 of 10 Abstracts search results

Document: 

SP278-05

Date: 

March 1, 2011

Author(s):

M.A. Alhassan and S.M. Ashur

Publication:

Symposium Papers

Volume:

278

Abstract:

It is generally accepted that the latex-modified concrete (LMC) overlay is a superior protection system for bridge decks. The incorporated latex acts as a plasticizing agent providing good workability even for low water/cement ratios. When exposed to air, the latex polymerizes forming a membrane around the hydration products resulting in a lower permeability and inherent flexibility to resist freeze and thaw cycles. Nevertheless, the latex imposes constructability limitations that dramatically increase the initial installation cost of the LMC overlay. The latex starts to polymerize within 15-30 minutes dictating the need for mobile mixers to install the LMC overlay. The cost of the latex adds to the cost of the LMC especially when the oil price increases. This paper presents and discusses the effect of different types and combinations of macro and micro synthetic fibers on the major performance characteristics and constructability of the fibrous LMC overlay.

DOI:

10.14359/51682504


Document: 

SP278-08

Date: 

March 1, 2011

Author(s):

E.M. Soliman, U.F. Kandil and M.M. Reda Taha

Publication:

Symposium Papers

Volume:

278

Abstract:

This research examines the significance of using carbon nanotubes (CNTs) on the mechanical characteristics and microstructural features of latex modified mortar (LMM). CNTs have been introduced recently as a new nanoscale material with excellent mechanical properties. This work examines the ability of various CNTs’ contents to alter the mechanical properties of latex modified mortars. Compression and tension tests were performed on LMM specimens with and without CNTs at 7 and 28 days of age. The experimental investigations showed that CNTs can enhance the strength and deformation characteristics of LMM. Microstructural investigations showed CNTs to be well dispersed and bonded to the polymer latex matrix. It is concluded that CNTs can be a useful alternative to enhance the mechanical characteristics of polymer modified cement composites.

DOI:

10.14359/51682507


Document: 

SP278-02

Date: 

March 1, 2011

Author(s):

A.S. El-Dieb, T.A. El-Maaddawy and A.A.M. Mahmoud

Publication:

Symposium Papers

Volume:

278

Abstract:

Maintaining satisfactory moisture content in concrete during its early ages is very important to develop required properties. Retaining free water of the mixture for a longer period will have a beneficial effect similar to that of curing. Self-curing mixtures will be very beneficial especially in regions where water is not adequately available. Polymers in concrete have received considerable attention over the past two decades. This study investigates using laboratory synthesized water-soluble polymers: polyethylene glycol (PEG) and polyacrylamide (PAM) as self-curing agents and its effect on the degree of hydration, water absorption, permeable pores and microstructural characteristics of Portland cement mixtures without and with 8% silica fume replacement. Portland cement mixtures including PEG or PEG+PAM as self-curing agents showed a better quality compared to that of the non-cured mixtures. Mixtures incorporating 8% silica fume including a mixture of PEG and PAM as self-curing agent had a better quality compared to that of the mixture including only PEG especially at later ages.

DOI:

10.14359/51682501


Document: 

SP278-09

Date: 

March 1, 2011

Author(s):

M.M. Sprinkel

Publication:

Symposium Papers

Volume:

278

Abstract:

Hydraulic cement concrete overlays made with latex-modified concrete (LMC) and silica fume concrete (SFC) are typically used to extend the life of bridge decks because the overlays reduce the infiltration of water and chloride ions. Rapid concrete overlays can be used to reduce lane closure time and associated traffic congestion and road user costs. LMC prepared with very early hardening cement (LMC-VE) has been used as a rapid overlay for bridge decks in Virginia since 1997. This paper compares the performance of LMC-VE overlays to that of conventional LMC and SFC overlays. Results indicate that LMC-VE overlays are performing as well or better than LMC and SFC overlays. LMC-VE has become a standard overlay for situations in which lane closures cause major traffic congestion. The higher cost of materials for LMC-VE overlays can be off set by lower costs for traffic control. Including user cost savings make LMC-VE overlays even more cost effective.

DOI:

10.14359/51682508


Document: 

SP278

Date: 

March 1, 2011

Author(s):

Editor: Mahmoud Reda Taha / Sponsored by Committee 548

Publication:

Symposium Papers

Volume:

278

Abstract:

This CD-ROM contains nine papers sponsored by ACI Committee 548. The extended use of polymers in concrete has grown significantly in the last two decades. This is demonstrated from the common use of epoxy to repair cracks, to the use of polymer concrete overlays to protect bridge decks. The papers provide insight into the current state of research and development for the use of polymers in concrete and new trends that will shape the frontiers of the polymer concrete industry in the near future. Note: The individual papers are also available. Please click on the following link to view the papers available, or call 248.848.3800 to order. SP-278

DOI:

10.14359/51682357


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