Lime cement

Of course, lime is no longer used to light up the stage, but it is still used today in an application that has been around for millennia—making concrete. In fact, the Great Wall of China is made of lime cement. 

For compacted, low-permeability soil liners, the U.S. EPA draft guidance recommends natural soil materials, such as clays and silts.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. 

On-site sandy soils can also be blended with other clay soils available in the area, but natural clay soil is likely to form chunks that are difficult to break down into small pieces. Bentonites, obtained in dry, powdered forms, are much easier to blend with on-site sandy soils than are wet, sticky clods of clay. Materials other than bentonite can be used, such as atapulgite, a clay mineral that is insensitive to attack by waste. Soils can also be amended with lime, cement, or other additives. 

It is possible to make soils more resistant to chemical attack. Many of the same methods used to lower hydraulic conductivity can stabilize materials against leachate attack, including greater compaction, an increase in overburden stress, and the mixing of additives such as lime cement or sodium silicate with the natural soil materials.25... 

The two other main types of human-made building cements, lime cement and gypsum cement, have been and still are used in many areas of the world. Both these cements require quite elaborate thermal procedures for producing their main components, which are slaked lime in lime cement and plaster of Paris in gypsum cement. Making them involves the calcination of an appropriate type of stone, a process that has been practiced since prehistoric times. Slaked lime is made by the calcination of limestone plaster of Paris, by the calcination of gypsum (see Textbox 33) (Cobum et al. 1990 Lea 1962). 

In a review of deep soil mixing techniques, Bruce et al. stated that large-scale soil mixing systems may cost 80,000 to 200,000 to mobilize (costs were reported to be lower for methods such as lime cement columns). Typical treatment prices for deep soil mixing technologies were estimated to range from 50 to 100/m (D207238, p. 4). 

Solidification/stabilization Refers to reducing the mobility of a contaminant in soils, other solids, or even liquid wastes by mixing them with Portland cement, lime, cement kiln dust, clays, slags, polymers, water treatment sludges, iron-rich gypsum, fly ash, and/or other binders. The process decreases the mobility of contaminants through physical encapsulation (solidification) and chemical bonding between the contaminants and the binders (stabilization). 

With the advent of dry wall finishes that replace the wet plaster wall finish, additional fire safety problems were presented. The lime, cement, and gypsum plaster previously used provided an incombustible surface and afforded some fire protection to the wood or steel framing of the building but many of the dry wall finishes are themselves combustible, offer little if any resistance to fire, and tend to increase the intensity of a fire by contributing additional fuel. 

Type of plaster Lime + Cement Cement (+lime ) Lime... 

On this point he notes the lime-cement employed by the Ancients in Scotland appears to be much firmer than that which has been made in modern times, ibid., 435. 

Figure 6.3 Barrier wall constructed by deep soil mixing, using a lime-cement slurry. (Courtesy of Underpinning and Foundation, SKANSKA, Maspeth, NY.)...

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