Cementitious systems

C. Gervais, and S. K. Ouki, Performance study of cementitious systems containing zeolite and silica fume Effects of 4 metal nitrates on the setting time, strength and leaching characteristics. J. Hazard. Mater., 93,187-200, 2002. 

Cement hydration and epoxy polymerization occur simultaneously to form a structure that is similar to the latex-modified cementitious system. Epoxy systems develop high strength, adhesion and have low permeability, good water resistance and chemical resistance. A major advantage of this system is that it can be cured under moist or wet conditions. According to a recent study, the epoxy-modified mortars can be made without the hardeners with superior properties to those obtained with conventional epoxy mortars [89, 90]. 

Tishmack, J. K., Olek, J. Diamond, S. 1999. Characterization of high-calcium fly ashes and their potential influence on ettringite formation in cementitious systems. Cement, Concrete, and Aggregates, 21, 82-92. 

Zhang, M. 2000. Incorporation of Oxyanionic B, Cr, Mo, and Se into Hydrocalumite and Ettringite Application to Cementitious Systems. PhD thesis, University of Waterloo, Waterloo, Canada. 

There are probably several mineral phases, particularly for the highly alkaline systems, that remain to be discovered. Mixed hydroxides may control solubility. Calcium zincate (CaZn2(OH)6), for example, is thermodynamically more stable than Zn(OH)2 above pH 11.5 and may be important in cementitious systems. Another group of minerals is that of the hydrotalcite-like minerals, the layered double hydroxides (LDH, M2+2M3+l/yXy (OH)6 where X is an anion). Cobalt, Ni and Zn can form such minerals (Johnson Glasser 2003) under neutral to alkaline conditions. For the majority of species, however, solubility-limiting phases do not appear to control dissolved concentrations. 

Laboratory tests of stationary diffusion of chloride ions in cementitious systems have been conducted since the 1970s for purposes of research and classification of different concrete compositions [5]. 

Bonding agents may also be applied in some cases on the concrete surface in order to enhance adhesion of the repair mortar. These may be cementitious systems (cement paste or fine mortars), polymer latex or epoxy systems [4]. Epoxy systems should be used carefully since they create a moisture barrier between the substrate and the repair material, which can result in failure of the repair if moisture is trapped in the concrete. 

MacKay MH, Emery JJ (1994) Stabilization/solidification of contaminated soils and sludges using cementitious systems selected case histories (Transportation Research Record No 14). Transportation Research Board, Washington, DC, p 315... 

Uses Antishrink agent in cementitious systems coalescing agent in redispersible emulsion paints... 

Chem. Desalp. Blend of glycols with inorg. carrier Uses Antishrink agent for cementitious systems coalescent for powd. paints... 

Bentur A. and Kolver K. Evaluation of early age cracking characteristics in cementitious systems. Materials and Structures 2003 36(4) 183-190. 

Onysko SJ, Kleinmann RLP, Erickson PM (1984) Ferrous iron oxidation by Thiobacillus ferroxo-dans inhibition with benzoic acid, sorbic acid, and sodium lauryl sulfate with benzoic acid, sorbic acid, and sodium lauryl sulfate. Appl Environ Microbiol 48 229-231 Osterloh F, Saak W, PoU S, Kroeckel M, Meier C, Trautwein AX (1998) Synthesis and characterization of neutral hexanuclear iron sulfur clusters containing stair-like [Fe6(u3-S)4(u2-SR)4] and nest-like [Fe6(u3-S)2(u2-S)2(u4-S)(u2-SR)4]. Inorg Chem 37 3581-3587 Palamo A, Femaddez-Jimenez A, Kovalchuk G, Ordonez LM, Naranjo MC (2007) Opc-fly ash cementitious systems study of gel binder produced during alkaline hydration. J Mater Sci 42 2958-2966... 

Upon heating, hardened cement pastes undergo chemical reactions (for example, thermal decomposition of the hydrates present and a loss of chemically bound water). These processes may be associated with a decline or even a complete loss of strength, but in some cementitious systems an increase of strength may also be observed. 

A variety of industrial by-products and natural starting materials qualify as mineral additions, and may be used as constituents of inorganic binders or cementitious systems. These materials may possess cementitious properties by themselves, or they may be latent hydranlic, pozzolanic, or even non-ieactive. 

In conclusion, the resistance of aluminous cement based concrete to most chemical corrosive agents is outstanding, provided that the mix is produced with a sufficient cement content and with a low water/cement ratio, and is properly compacted and cured. Like other hydrated cementitious systems, hardened calcium alununate cement pastes decompose and undergo chemical reactions upon heating ... 

Calcium aluminate phosphate cementitious systems are obtained by combining calcium aluminate cement with alkali or ammonium phosphates or polyphosphates (Sugama and Carciello, 1991 Ma and Brown, 1992, 1994 Walter and Odler, 1996). They are discussed in section 12.3. 

Some organic polymers may be combined with inorganic cements to yield materials with unique properties. A precondition for such application is a sufficient stability of the polymer in a high-pH environment, typical for most cementitious systems. 

Cementitious systems modified with organic polymers 213... 

Cementitious systems modified with otganic polymers 223... 

Odler, L, and Liang, L. (1992) Physico-mechanical properties of cementitious systems modified by elastomer dispersions, in Proceedings 7th International Congress on Polymers in Concrete, Moscow, pp. 201-212. 

Cementitious systems modified with oiganic polymers 227... 

A variety of powdered natural materials and industrial by-products rich in Si02 and AI2O3 may be activated with suitable alkaline activators to yield a cementitious system that sets and hardens if mixed with appropriate amounts of water. 

Cementitious systems based on alkali-activated fly ashes are discussed in section 9.1.5. 

The term geopolymeric cements or geopolymers is not clearly defined. In general, they are inorganic cementitious systems in which a three-dimensional zeoUtic framework has been formed in a poly condensation reaction. 

In many applications cementitious systems are exposed to chemical attack that may cause their gradual degradation, and may affect their service life adversely. Thus adequate measures must be taken to prevent or minimize this type of degradation and to ensure proper performance of the material. 

A typical feature of hardened inorganic cement pastes is their low tensile/ compressive strength ratio. To improve this ratio and to lower the brittleness of the material, cementitious systems may be reinforced with suitable fibers randomly distributed within the cement matrix (Fig. 25.1). 

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