Toughening the Macro Defect Free (MDF) Cements

2010 ◽  
Author(s):  
Alberto D’Amore ◽  
Luigi Grassia ◽  
A. D’Amore ◽  
Domenico Acierno ◽  
Luigi Grassia
Keyword(s):  
Mdf Cements

Macro-Defect-Free (MDF) Cements with High Moisture Resistance: Chemical, Thermal, SEM and Magnetometric Study

2003 ◽  
Vol 90-91 ◽  
pp. 365-370 ◽  
Author(s):  
Subhash C. Mojumdar ◽  
A. Ray ◽  
Milan Drábik ◽  
A. Cigáň ◽  
František Hanic ◽  
...  
Keyword(s):  
Moisture Resistance ◽  
High Moisture ◽  
Mdf Cements

Effect of Epoxy Resin Addition on the Moisture Sensitivity of Macro Defect Free Polymer-Cement Composites

2011 ◽  
Vol 466 ◽  
pp. 65-72 ◽  
Author(s):  
Ozgur Ekincioglu ◽  
M. Hulusi Ozkul ◽  
Yoshihiko Ohama ◽  
Silvia Patachia ◽  
Georgeta Moise
Keyword(s):  
Bisphenol A ◽  
Epoxy Resins ◽  
Production Method ◽  
Diglycidyl Ether ◽  
Poly Vinyl Alcohol ◽  
Cement Pastes ◽  
Force Microscopy ◽  
Atomic Force ◽  
Roll Mill ◽  
Mdf Cements

Macro-defect-free (MDF) cements are cement-polymer composites and were developed by Birchall et al. three decades ago. The composites are produced by mixing small amounts of polymer and water with cement. However, they have a different production method than that of cement pastes, which was inspired by rubber production. Mixtures of cement, polymer and water are processed by using a two-roll mill. The composites are known with their high flexural strengths. Unfortunately, there are not any known commercial products using MDF cements because of their poor durability under moisture. In this study, MDF cements were prepared by using poly(vinyl alcohol--vinyl acetate) PVA, calcium aluminate cements and two different types of epoxy resins. Epoxy resins were a diglycidyl ether of bisphenol A and a mixture of a diglycidyl ethers of bisphenol A and F. Durability performance was compared with respect to biaxial flexural strengths, contact angle and atomic force microscopy (AFM) for the specimens stored in water.

Indentation Fracture of Macro-Defect-Free (MDF) Cements

1989 ◽  
Vol 179 ◽  
Author(s):  
Yeong-Shyung Chou ◽  
J. J. Mecholsky ◽  
M. R. Silsbee ◽  
D. M Roy ◽  
J. H. Adair ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Fracture Surface ◽  
Surface Analysis ◽  
Polymer Content ◽  
Indentation Fracture ◽  
Fracture Surface Analysis ◽  
Mdf Cements ◽  
Good Agreement

AbstractThe fracture toughness of MDF (macro-defect-free) cement with different polymer contents has been investigated by the indentation-strength method and fracture surface analysis. It was found that the fracture toughness obtained by these two different techniques showed good agreement for the low (3 wt.%) polymer cement. The ultimate (apparent) toughnesses are 1.3 Mpam1/2 for low polymer content and 2.2 Mpam1/2 for high (8 wt.%) polymer content cement. Different microcracking and sponge-like microstructures have been observed and discussed.

Recent developments in macro-defect-free (MDF) cements

2009 ◽  
Vol 23 (5) ◽  
pp. 1761-1767 ◽  
Author(s):  
S. Donatello ◽  
M. Tyrer ◽  
C.R. Cheeseman
Keyword(s):  
Recent Developments ◽  
Mdf Cements

Macro Defect Free (MDF) Cements

1987 ◽  
Vol 12 (1) ◽  
pp. 21-25 ◽  
Author(s):  
K. KENDALL
Keyword(s):  
Mdf Cements

MDF Cements for Low Temperature Applications

1986 ◽  
pp. 201-207 ◽  
Author(s):  
B. A. Hands ◽  
A. J. Smith ◽  
G. W. Groves ◽  
D. D. Double
Keyword(s):  
Low Temperature ◽  
Mdf Cements ◽  
Temperature Applications

scholarly journals The effect of carbon nanotubes on the mechanical and damping properties of macro-defect-free cements

2020 ◽  
Vol 27 (1) ◽  
pp. 28-40 ◽  
Author(s):  
Zhang Wenhua ◽  
Wu Peipei ◽  
Zhang Yunsheng ◽  
Zeng Weizhao ◽  
Yang Fenghao
Keyword(s):  
Carbon Nanotubes ◽  
Flexural Strength ◽  
Loss Factor ◽  
Strengthening Mechanism ◽  
Crack Deflection ◽  
Damping Properties ◽  
Negative Contribution ◽  
Fiber Bridging ◽  
Interface Transition Zone ◽  
Mdf Cements

AbstractThe effect of CNTs on the mechanical and damping properties of macro-defect-free (MDF) cements was studied, and polyvinyl alcohol (PVA) fibers were also studied as a contrast. It was found that the compressive strength of MDF cements was not significantly affected by the two types of fibers. The CNTs enhanced the flexural strength of MDF, while PVA fibers made negative contribution. The strengthening mechanism of flexural strength of MDF cements by CNTs can be summarized as fiber bridging, crack deflection and fiber slippage. For the damping properties, the proper contents of CNTs and PVA fibers improved the loss factor significantly. The interface transition zone (ITZ) between the PVA fibers and matrix was large, which was favorable for fiber slippage. The damping property of MDF cements with CNTs was mainly due to the slippage between the inner tubes of the CNTs rather than the slippage between the CNTs and matrix.

The relation between porosity, microstructure and strength, and the approach to advanced cement-based materials

1983 ◽  
Vol 310 (1511) ◽  
pp. 139-153 ◽  
Keyword(s):  
Elastic Modulus ◽  
Fracture Energy ◽  
Cement Paste ◽  
Compression Strength ◽  
Bending Strength ◽  
Cement Pastes ◽  
Cement Based Materials ◽  
Mdf Cements

A theory is formulated to connect the strength of cement paste with its porosity. The theory shows that bending strength is largely dictated by the length of the largest pores, as in the Griffith (1920) model, but there is also an influence of the volume of porosity, which affects toughness through changing elastic modulus and fracture energy. Verification of this theory was achieved by observing the large pores in cement, and then relating bending strength to the measured defect length, modulus and fracture energy. The argument was proved by developing processes to remove the large pores from cement pastes, thereby raising the bending strength to 70 MPa. Further removal of colloidal pores gave a bending strength of 150 MPa and compression strength up to 300 MPa with improved toughness. Re-introduction of controlled pores into these macro-defect-free (mdf) cements allowed Feret’s law (1897) to be explained.

Microstructure-Property Relationships in Macro-Defect-Free Cement

MRS Bulletin ◽  
1993 ◽  
Vol 18 (3) ◽  
pp. 72-77 ◽  
Author(s):  
Jennifer A. Lewis ◽  
Waltraud M. Kriven
Keyword(s):  
Raw Materials ◽  
Cement Composite ◽  
Water Soluble ◽  
Minimal Amount ◽  
Metal Powders ◽  
Water Soluble Polymer ◽  
Cement Pastes ◽  
Mdf Cements ◽  
Novel Processing ◽  
Entrapped Air

The term “macro-defect-free” refers to the absence of relatively large voids (or defects) that are normally present in conventional cement pastes due to entrapped air or inadequate mixing. A decade ago, Birchall and co-workers developed a novel processing method that avoids the formation of these strength-limiting defects. This method, outlined schematically in Figure 1, consists of mixing hydraulic cement powder, a water-soluble polymer, and a minimal amount of water under high shear to produce a macro-defect-free (MDF) cement composite. Several cement/polymer systems can be processed by this flexible technique, although the calcium aluminate cement/polyvinyl alcohol-acetate (PVA) copolymer system is most common: MDF cements display unique properties relative to conventional cement pastes. For example, the flexural strength of MDF cement is more than 200 MPa as compared to values on the order of 10 MPa for conventional pastes. One can view MDF cements as a type of “inorganic plastic.” As is the case with plastic processing, fillers such as alumina, silicon carbide, or metal powders can be added to MDF cement to modify its performance properties (e.g., abrasion resistance, thermal or electrical conductivity, and hardness). The combined attractiveness of inexpensive raw materials and flexible, low-temperature processing has generated great interest in this new class of advanced cement-based materials.

scholarly journals A Few Trials of Water Resistance-Improving Techniques for MDF Cements

1997 ◽  
Vol 8 (1) ◽  
pp. 225-231
Author(s):  
Toshimitsu Kobayashi ◽  
Yoshihiko Ohama ◽  
Katsunori Demura
Keyword(s):  
Water Resistance ◽  
Mdf Cements
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