The most commonly used binder in mass stabilization is cement but the use of lime is also possible in many cases (lime cement). Additionally, various reactive by-products originating from industrial processes may be used alongside as a mixture component. These include such by-products as slags, fly ash, and/or gypsum components. The use of industrial by-products allows for achieving stabilized masses with a better technical and/or environmental quality, as well as it decreases the overall costs of the binder agents.
The main factors influencing the selection process are target strength, material price and its availability. Other issues to be considered include, among others, curing time, stress-strain properties, and in some cases also impacts on leaching and permeability features. It is also necessary to take into account such characteristics of the machinery to be used as, the maximum binder feeding capacity and the number of the binder subcomponents. It is also important whether dry binder is fed or it possible to use moistened binding agent, as for instance, stockpile fly ash.
Other binders commonly utilized in mass stabilization include by-products of industrial processes, such as various slags, fly ashes, and gypsum products. In most cases, these materials are used together with commercial binder components with the objective to improve the technical and environmental properties of the final structure, and also in order to decrease binder costs. In some special cases, it is possible to carry out stabilization/solidification of soil masses only with the use of by-products as binder components.
The use of the so called by-product binder components commonly increases to some extent the overall amount of binder, but on the other hand it also allows for significant cost savings. The economic advantage makes the mass stabilization method more attractive and competitive. The drawback of the increased amount of binder lies in the fact that it may slightly slow down the actual execution of stabilization work.
There are several issues that need to be taken into consideration while using slags, fly ashes or gypsum products as binder components including the following:
- availability of the material, its quality and variations in quality
- temporary storage needs
- ways of processing and transporting the material at the construction site
- permitting issues associated to the use of secondary materials