Hydraulic index limes

For compacted, low-permeability soil liners, the U.S. EPA draft guidance recommends natural soil materials, such as clays and silts. However, soils amended or blended with different additives (e.g., lime, cement, bentonite clays, and borrow clays) may also meet the current selection criteria of low hydraulic conductivity, or permeability, and sufficient thickness to prevent hazardous constituent migration out of the landfill unit. Therefore, U.S. EPA does not exclude compacted soil liners that contain these amendments. Additional factors affecting the design and construction of CCLs include plasticity index (PI), Atterburg limits, grain sizes, clay mineralogy, and attenuation properties. 

The limestone is generally calcined in shaft kilns [16.59], which must be controlled closely to ensure that as much of the silica and alumina as possible reacts, without sintering the free lime, lypical calcining temperatures are 950 to 1250 °C the required temperature rises as the cementation index (see section 26.9.2) increases (i.e. from feebly to eminently hydraulic limes). 

Hydraulic limes are also classified in terms of the cementation index (Cl) [26.45], based on the analysis of the lime. This is calculated by the following equation ... 

Cementation Index (Cl) is used to eategorise hydraulic limes (see seetion 16.10.1). 

It must be noted that the lime is normally used for lowering the plasticity index of the material and to temporarily modify the materials to ease construction. Permanent increase of the strength of the material can be achieved only when used in a mixture with other hydraulic binders. Hence, the use on its own is very limited. 

Disintegration Index. A measure of the durability of a hydraulic cement proposed by T. Merriman Engng. News Record, 104,62,1930). The test involves shaking with a lime-sugar solution followed by titration of one aliquot against HQ with phenolphthalein as indicator and another with methyl orange as indicator. The Disintegration Index is the difference between the two titrations. The test was superseded by the test now known as the merriman test (q.v.). 

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See also in sourсe #XX -- [ , ]

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