Cement-based materials

Young, J.F. (1985) Very high strength cement-based materials. Mater. Res. Soc. Symp. Proc. 42. 

Zinc will initially react with cement-based materials with the evolution of hydrogen. This reaction can be controlled by the presence of soluble chromate either in the cement (over 70 ppm) or as a chromate passivation treatment to the zinc surface. Zinc can therefore be used to provide additional protection to steel in concrete. It is more effective in cmbonated concrete than in chloride-contaminated concrete. 

The SPI and the SPRITE techniques have been applied to numerous concrete material problems. Some of these applications are presented in the following discussion. It is very important, however, to point out that these measurement techniques are not limited to cement-based material problems, but are fairly general in application. They can be, and have been, applied to many different material science problems. 

The measurement applications of density weighted drying profiles, water ingress, water phase transitions, crack detection, chlorine, sodium and lithium imaging applied to cement-based materials can be easily translated to other porous media. Density weighted MRI will no doubt prove to be a powerful tool in material science research. 

Recent applications of relaxation dispersion measurements to concrete or cement-based materials are promising for characterizing reactive nanopor-ous materials, the structure of which may evolve over time (75-78). The MRD profiles have provided, for the first time, a direct means for characterizing the specific surface area, Sp, of a hydrated cement-based material (79), without exposing the sample to extremes of temperature or pressure (80-83). The interest in such a surface area is to provide information on the microsctruc-ture and its impact on macroscopic or structural properties. The method is based on a clear separation of surface and bulk contributions of the overall... 

Shiotani, T., Bisschop, J. and Van Mier, J.G.M. (2003) Temporal and Spatial Development of Drying Shrinkage in Cement-based Materials. Engineering Fracture Mechanics... 

Merchant, I.J., Macphee, D.E., Chandler, H.W. and Henderson, RJ. Toughening cement based materials through the control of interfacial bonding , Cement Concrete Research 31 (2001) 1873-1880. 

A. B. Abell, K. L. Willis, and D. A. Lange, Mercury intrusion porosimetry and image analysis of cement-based materials, J. Colloid Interf. Anal. 211, 39-44 (1999). 

Bonen D, Sarkar SL (1995) The effects of simulated environmental attack on immobilization of heavy metals doped in cement-based materials. J Hazard Mater 40 321-335... 

CjAHg is the only stable ternary phase in the CaO-AUOj H,0 system at ordinary temperatures, but neither it nor any other hydrogarnet phase is formed as a major hydration product of typical, modern Portland cements under those conditions. Minor quantities are formed from some composite cements and, in a poorly crystalline state, from Portland cements. Larger quantities were given by some older Portland cements, and are also among the normal hydration products of autoclaved cement-based materials. CjAHg is formed in the conversion reaction of hydrated calcium aluminate cements (Section 10.1). 

Very high strength cement-based materials... 

Because cement-based materials are well-known insulators, another avenue for further research and product development is the strategic use of fiber-cement composites for sound and heat insulation. Such products might be composed wholly of fiber-cement (likely aerated) or where fiber cement is just one component in an insulating panel or member. 

For cement-like materials an overestimation of the pore size is expected, since the contact angle of < 130° is much lower than the standard value of 140°. However, the availability of cement-based materials with an ordered pore structure in the appropriate pore size range is limited and as a consequence these results cannot be discussed here. 

The high cost of resins used in the production of polymer concrete (PC) makes the material expensive relative to cement-based materials. Not surprisingly, a recent survey ranked lower cost resins as the most important future need for PC [1], Recently, some work has been done on the production of unsaturated polyester resins based on recycled poly (ethylene terephthalate), PET [2], The PET wastes are typically found in used beverage bottles, and many states have passed legislation to collect and recycle these bottles. If specially formulated, the unsaturated polyester could be used in the production of PC [3],... 

Cement-based materials, that are widely used in nuclear industry, concern two main fields of applications ... 

Figure 6 Physico-chemical parameters and their couplings involved in the radiolysis of cement-based materials at the level of a waste form. Heterogeneous equilibria (solid solution and solution-gas) are located by a double red arrow.

Although simulations happen to be the most economic and fastest way to carry out the evaluation ofthe Hj source term in various cement-based materials, it is advisable to perform periodical experiments, preferably following an important conceptual modification, in order to check certain predictions and also to fix certain parameters of the model. These experiments generally are related with the test-bars of cement material irradiated in closed vessel or the material poured within air-tight mini-containers (Fig. 8). 

Cement-Based Materials. Eds. Colombet, R, Grimmer, A.R., Zanni, H., Sozzani, R, Springer Verlag, New York, p. 47. 

R699 S.-H. Hong, Advanced Cement Based Materials Center in USA , Seramisutu, 1999, 2, 62... 

Center for Advanced Cement-Based Materials, Northwestern University http //acbm.northwest-ern.edu/. 

S. Peer, Nondestructive evaluation of moisture and chloride ingress in cement-based materials using near-field microwave techniques, M.S. Thesis, Electrical and Computer Engineering, University of Missouri-Rolla, MO, December 2002. 

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