Natural pozzolanas react quickly and well with lime. ❋ Unknown (1998)
In producing blended cements, almost all types of common pozzolanas can be used. ❋ Unknown (1995)
Artificial pozzolanas are produced from a number of industrial and agricultural wastes which are highly siliceous. ❋ Unknown (1995)
Lime was already discussed in the previous sections, therefore, in the following parts, only gypsum, pozzolanas and blended cements will be briefly discussed. ❋ Unknown (1995)
Blended cements are either produced directly in cement plants (e.g. by mixing certain types of pozzolanas with cement clinkers and grinding them together) or they can be produced on site by mixing ordinary Portland cement (OPC) with finely ground pozzolanas. ❋ Unknown (1995)
As in the case of natural pozzolanas, the artificial pozzolanas are processed and mixed either with lime or cement to be used as binding material in low-cost construction or soil stabilization. ❋ Unknown (1995)
These pozzolanas, depending on the expected strength of the mortars, can reduce the use of lime by 20 to 30 per cent, but if mixed with cement, the substitution to cement can even be higher. ❋ Unknown (1995)
Energy-saving opportunities using pozzolanas as replacement of cement ❋ Unknown (1995)
Even though processing pozzolanas and producing them in a usable form, to be mixed with lime or cement, requires some energy, experiment and extensive research work have shown that the sum of energy used in this process is less than the energy used in the substituted cement or lime. ❋ Unknown (1995)
Needless to emphasis that the environmental impact of the use of industrial and agricultural wastes is another reason which makes the use of pozzolanas attractive. ❋ Unknown (1995)
The most important low-cost binders include: lime gypsum, pozzolanas and blended cements. ❋ Unknown (1995)
The blending of certain carbonaceous materials such as granulated slag, fly-ash and other pozzolanas with cement makes it possible to produce more cement from the same amount of clinker and, thus, reduce the final consumption of energy per ton of cement produced. ❋ Unknown (1995)
However, among the different types of pozzolanas, furnace slag has been widely used in the process of producing blended cement, which is very popular in both developed and developing countries and for which relevant standards have already been established. ❋ Unknown (1995)
The replacement percentages of pozzolanas vary from 15 to 50 per cent resulting in an energy saving of up to 40 percent. ❋ Unknown (1995)
The most commonly occurrences of natural pozzolanas are volcanic ashes and pumice powder. ❋ Unknown (1995)
Cements containing other materials such as slag, fly-ash and other pozzolanas can also be used, although these will only be available close to steel plants power stations and similar localities. ❋ Unknown (1994)
Natural pozzolanas react particularly well with lime. ❋ Unknown (1994)
The cement component in concrete can be reduced by a careful mix design, grading of aggregates, testing, quality control and by substitution with cheaper pozzolanas. ❋ Unknown (1993)
Burnt-clay pozzolanas (known in India as surkhi) are derived either by pulverizing or grinding waste or reject bricks and tiles or by firing specially selected clays in purpose-designed kilns and then grinding them. ❋ Unknown (1989)
