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Cement-fly ash

L. V. Palij, V. E. Akhrimenko, A. K. Kuksov, V. M. Medentsev, and V. I. Panov. Plugging solution for oil and gas wells—contains Portland cement, fly ash, sodium or calcium sulphate and additionally hydrosil, to increase adhesion of cement rock to casing string. Patent SU 1802087-A, 1993. [Pg.444]

Terrafix units are trailer-mounted, fully transportable units that can be operational within hours after arrival at the site. The units are designed to screen out large material such as rocks and metal parts as well as remove ferrous material using magnetic separation. The remaining material is then mixed in a pug mill with cementitious materials (i.e., cement, fly ash, pozzilime) and/or silicates to produce a material in which the heavy metals are chemically fixed. [Pg.1039]

Fly ash, as it is a large-volume industrial waste, is both cheap and abundant, so that there is an economic incentive to use fly-ash-modified cements. In addition, C02 is also produced as a waste by-product of industrial processes (power generation, cement manufacture, etc.), and its permanent sequestration into cement is an added environmental benefit. A fully carbonated Portland cement permanently sequesters about 130 L of C02 per kilogram of cement. Figure 15.8 shows the structural and chemical modifications produced in cemented fly ash microspheres as a result of the supercritical C02 treatment. As is the case with fly ash, kiln dusts are primarily siliceous, so that the same benefits can be derived from their use as modifiers in immobilization and S/S matrices. [Pg.253]

Figure 15.8. Micrographs of cemented fly ash microspheres (a) before sc C02 treatment, (b) after sc C02 treatment. Figure 15.8. Micrographs of cemented fly ash microspheres (a) before sc C02 treatment, (b) after sc C02 treatment.
Wang SY, Vipulanandan C (1996) Leachability of lead from solidified cement-fly ash binders. Cem Concr Res 26 895-905... [Pg.188]

Effect of calcium carbonate and cement/fly ash additives on chemical stabilization of fine-grained sediment from Hamburg harbour (Calmano et al., 1986)... [Pg.142]

Laboratory studies on the evaluation and efficiency of stabilization processes were performed by Calmano et al. (1988) on Hamburg harbor mud, using acid titration curves for limestone and cement/fly ash stabilizers. Best results are attained with calcium carbonate, since the pH-conditions are not changed sigmficantly upon addition... [Pg.174]

Either pozzolanic or self-cementing fly ash can be used in flowable fill... [Pg.120]

In Japan, calcium silicate-SBR latex-glass fiber-based compos-itesi or portland cement-fly ash-SBR latex-carbon fiber-based compos-itesi l have recently received much attention as new artificial wood. Table 8.3 gives die comparison of the properties of the calcium silicate-SBR latex-glass fiber-based artificial wood with natural wood.1 1... [Pg.217]

One method of lead fixation is to precipitate it as a relatively insoluble hydroxide, carbonate or phosphate. The solubility of lead as lead hydroxide is 133 mg/L Pb, as lead carbonate it is 0.85 mg/L Pb and as lead phosphate it is 0.11 mg/L Pb. However, all of these precipitates are soluble in acid or highly alkaline environments. Minimum lead levels require that the pH be maintained between 8 and 10. Another method of lead fixation is waste encapsulation. Many test have been done to use Portland cement by itself and in combination with aluminum sulfate, sodium silicate and ammonium phosphate. Instead of Portland cement, fly ash alone or in combination with lime can also be used. All of the above methods rely on maintaining a slightly alkaline environment. In an acidic environment, the alkaline material will eventually be leached, and the lead then becomes soluble at very high levels. [Pg.940]

The materials for the base and sub-base course are unbound aggregate mixtures or hydraulically bound aggregate mixtures. The aggregates may be crushed granular materials, manufactured materials from rock deposits or industrial by-products (slags) or recycled materials. The hydraulic binders, in the case of bound materials, are cement, fly ash, slag, lime, a mixture of some of them or factory-blended hydraulic binders for road use. [Pg.464]

The hydraulic binders or constituents such as cement, fly ash, slags and lime should comply with CEN EN 197-1 (2011), CEN EN 14227-4 (2013), CEN EN 14227-2 (2013) and CEN EN 14227-11 (2006), respectively. Additionally, any other hydraulic road binder, that is, factory-blended hydraulic binder for road use, may also be used, provided it complies to CEN EN 12447-5. [Pg.474]

The distinct types of CSM used for the construction of base/sub-base layer are as follows (a) cement-treated aggregate (CTA) or cement-treated base (CTB), (b) lean concrete (LC), (c) soil cement (base course), (d) lime-cement-fly ash base or pozzolanic-stabilised mixture, (e) lime-stabilised soil (LSS) and (f) open-graded cement stabilised. [Pg.479]

When MEPDG is employed and lime-cement-fly ash material or soil cement is going to be used again, the flexural strength needs to be determined, according to AASHTO T 97... [Pg.481]

The structural layer coefficients (afj depend on the type and function of layer material. These are asphalt concrete, granular base, granular sub-base, cement-treated and bituminous base. In order to estimate the structural layer coefficients, different charts have been developed. A sample of charts for asphalt concrete and granular base is shown in Figures 13.8 and 13.9. For other materials such as lime, lime fly ash and cement fly ash, the methodology suggests each agency to develop relevant charts. [Pg.549]

Alternatively, fly ash may be introduced directly into the fresh concrete mix as a separate component, rather than as a constituent of the cement. To do this, Portland cement, fly ash, and mixing water, together with the aggregate, are mixed in the concrete mixer to produce fly ash concrete. [Pg.129]

In the system Portland cement-fly ash-water the initial hydration of the clinker phases, especially those of tricalcium silicate and tricalcium aluminate, progresses much faster than that of the ash. Just as in the hydration of pure Portland cement, a C-S-H phase, ettringite, and calcium hydroxide are formed as the first hydration products. Any alkali sulfate salts, commonly present in the clinker, also dissolve and convert to alkaU hydroxides and calcium sulfate in a reaction with calcium hydroxide. The alkalinity of the liquid phase increases, and may exceed pH=13. [Pg.131]

The volume of pores of Portland-fly ash cements pastes tends to be greater than that of similar pastes made from pure Portland cement, but the pore stracture tends to be finer as long as the cement/fly ash replacement ratio is not excessive (above about 30%) (Li and Roy, 1986 Berry eta/., 1989). [Pg.133]

Carette, G.G. et al. (1986) Development of heat curing cycles for Portland cement fly ash... [Pg.151]

Expansion cement Fly-ash Patching cement Rapid setting cements Portland cement Hydraulic cement Reinforcement fibers Sake Fiber mesh Fly-ash Poly(vinyl alcohol) fiber Carbon fiber... [Pg.304]

Cement paste and cement - fly ash paste specimens and normal concrete specimens were partially exposed to Na2S04 and MgS04 solution under constant and fluctuating storage conditions respectively. After a pariod of exposure, the specimens were moved out from the solution and did not touch solution or water any more. The surface of the specimens was cleared by a thin blade and a soft brush. The samples for XRD and SEM were dried in a vacuum container with silica gel. [Pg.445]

Cement - fly ash paste partially exposed to Na2S04 solution under a constant storage condition... [Pg.447]

Cement - fly ash paste specimens (20x20xl50mm) were partially exposed to Na2S04 solution. After 5 months exposure imder the constant storage condition (20 C and 60%RH), some cracks were found near the up>p)er edge above solution level of the cement-fly ash p>aste specimen. Along the crack, small pieces were carefully broken off using a thin blade. The ESEM image of a small piece is shown in Fig. 11. [Pg.447]


See other pages where Cement-fly ash is mentioned: [Pg.1319]    [Pg.189]    [Pg.256]    [Pg.297]    [Pg.256]    [Pg.383]    [Pg.438]    [Pg.218]    [Pg.218]    [Pg.343]    [Pg.285]    [Pg.329]    [Pg.1004]    [Pg.142]    [Pg.73]    [Pg.261]    [Pg.85]    [Pg.256]    [Pg.482]    [Pg.192]    [Pg.104]    [Pg.104]    [Pg.104]    [Pg.174]    [Pg.447]   
See also in sourсe #XX -- [ Pg.211 , Pg.249 ]




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