Where does slaking collide?

In engineering geology, slaking is the disintegration of weak mudrocks and shales as they pass through cycles of wetting and drying, and a rock's resistance to it (its slake durability) governs how it performs as foundation, fill, or cut-slope material. Russell's 1982 study of two Ordovician shales in the slake-durability test examined what controls this breakdown. It names a wetting-driven loss of cohesion in rock, the same physical idea as soil-aggregate slaking scaled up, and quite distinct from the chemist's lime-making reaction that shares the word.[1]

Unit

The weight fraction of rock retained after standard wet–dry slaking cycles

Recovery means

Not applicable

Measured by

Reported as the slake-durability index from the standard two-cycle drum test, plus jar-immersion slaking ratings

In soil science, slaking is the rapid breakdown of soil aggregates when dry soil is suddenly wetted: water drawn into the pores compresses the trapped air until its pressure bursts the aggregate apart, making slaking a key index of a soil's structural stability. Zaher and Caron's 2008 work links the severity of slaking to pore occlusion and water-repellency during rapid wetting. It denotes destruction of structure by wetting, the opposite of the deliberate lime reaction, and the near-twin, at a finer scale, of the rock slake-durability meaning.[2]

Unit

The proportion of aggregates that disintegrate on rapid wetting

Recovery means

Not applicable

Measured by

Gauged by wet-sieving aggregate-stability indices and by comparing fast versus slow (capillary) wetting treatments

In lime technology and masonry, slaking is the exothermic reaction in which quicklime (calcium oxide) is combined with water to form calcium hydroxide (slaked lime, or with excess water lime putty), the binder of traditional mortars, plasters, and renders. Rosell and colleagues' 2014 study of the traditional slaking process shows how the way lime is slaked shapes the putty's particle size and workability. Here slaking is a deliberate chemical hydration that CREATES a material, the mirror image of the soil and rock meanings in which wetting destroys structure.[3]

Unit

The extent and rate of conversion of quicklime to calcium hydroxide

Recovery means

Not applicable

Measured by

Tracked by the slaking temperature rise and reaction rate (reactivity testing), the hydroxide yield, and the resulting particle size of the putty