Wetting-drying cycle

For waterproofing, sodium silicate concentrations below 30% are adequate concentrations between 35 and 70% are used for strength improvement. Grouts having 35 vol % or higher silicate resist deterioration on freeze—thaw or wet—dry cycles. Water permeability of sands can be reduced from 10 to 10 cm/s. Unconfined compressive strengths of stabilized sand can vary from 103 to 4130 kPa (15—600 psi) the normal range is between 690 and 1380 kPa. 

Table 6.3. Treatment levels of trace metals in the two Israeli arid soils incubated under the field capacity and wetting-drying cycle moisture regimes...

Table 6.6. Comparisons of the redistribution of metals in two Israeli soils at 3T treatment. Soils were incubated for one year under the saturated paste (SP), field capacity (FC) and wetting-drying cycle (Cycle) moisture regimes (% of the sum of fractions, as means of two replicates) (from Han et al., 2001a, with permission from Lippincott Williams Wilkins)...

Figure 7.4. Comparisons of decreases in NH4N03-extractable Zn, Ni and Cu in an Israeli loessial soil receiving metal nitrates and incubated under saturated paste, field capacity, and wetting/drying cycle moisture regimes (Han and Banin, 1997,1999, and Han et al., 2001a)...

In dehydrated CoAF the migration of Co2+ ions from Co2 to Co2a sites on heating (Fig. lb) allows the occupancy of the most active a-sites where Co2+coordinates four framework oxygens. The irreversible and progressive decline of catalytic activity during dry-wet-dry cycles is likely to be due to cation hydration and movement from those sites, thus, decreasing their occupancies. 

Berteau montmorillonite subjected to 2 (i), 5 ( ) and 10 ( ) wetting-drying cycles (101). Jurves re a simulation. Table VI shows these data for the (Ca - Cs ) equilibrium. Reproduced with permission from Ref. 101. Copyright 1985, The Clay Minerals Society. 

The early Earth was probably much more geothermaUy active than the Earth is today. [122] The continents of early Earth were most likely small with vertical profiles at, or near, sea-level. [125,181] Subaerial (in addition to submarine) tectonic rift zones and hydrothermal vent fields were probably ubiquitous and vigorous. [182] Extensive continental hydrothermal zones enriched in reducing inorganic and organic vent products and subject to wet/dry cycles were probably common. The low-profile shield continents of the early Earth must have been extensively surfaced with basalt and rhyolite, [183] some of which could have been porphyritic. 

J. R. (1991) The corrosion products of weathering steel and pure iron in simulated wet-dry cycles. Hyperfine Interactions 66 63—70... 

The dampproofmg admixtures will, therefore, improve the aesthetic qualities of concrete in terms of maintenance of a clean appearance over a prolonged period of time without adverse effects on other properties, and in the areas of freeze-thaw resistance, shrinkage under wet-dry cycling and reinforcement protection, may contribute beneficially. 

Lundquist, E. J., Scow, K. M., Jackson, L. E., Uesugi, S. L., and Johnson, C. R. (1999). Rapid response of soil microbial communities from conventional, low input, and organic farming systems to a wet/dry cycle. Soil Biol. Biochem. 31, 1661-1675. 

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