PowerCem Stabilisation Products. New to the UK
Why they are so effective.
RoadCem enhances and increases the strength and flexibility of stabilised road layers and improves the overall performance of cement bound materials used in road construction.
RoadCem modifies and extends the chemistry of the cement hydration process and extends the crystallization process by forming long needle crystalline structure.
It is able to delay or to speed up the hydration process of cement and can thus be used as a tool to custom designs the mixes of required performance.
Any type of existing site material that can be bound with RoadCem and which gives strength to the construction enabling it to be used in a road pavement.
This eliminates the need for material import and export and in so doing significantly reduces the cost of road construction and the environmental impacts. Its unique characteristics enable cost effective and rapid construction of high quality roads of different categories and rapid and effective stabilisation of soil for different purposes (embankments, dikes, supporting structures, building platforms etc.).
RoadCem is a product that is used in combination with cement and/or other pozzolanic materials such as pulverised fuel ash.
In order to understand how RoadCem works we first have to briefly explain how Cement and pozzolanic materials act as binders of different materials.
The five major compounds of the hydration process of Cement still remain the most important hydration products but the minor products of hydration change. Furthermore, the rate at which important hydration reactions occur and the relative distribution of hydration products changes
as a result of the addition of RoadCem.
In addition, the crystallization of calcium hydroxide accordingly occurs at different rates and the reduction of heat generation from the hydration reactions occurs.
There are more crystals formed during the reactions and the relevant crystalline matrix is much more extensive.
When adding RoadCem, the amount of water trapped as free water is reduced and the crystals grow into the empty void space.
This makes the product less permeable to water and more resistant to all types of attack that are either water dependant or water influenced. A bigger fraction of the water is converted to crystalline water than is the case with the reactions in the absence of RoadCem.
The reduced porosity and increased crystalline structural matrix increases compressive, flexural and breaking strength of the product and change the relative ratio between these strengths.
Heat evolved during hydration is reduced especially in phases III and IV indicating that some of the phase III and IV reactions might not be occurring or that different reactions are occurring.
Water continues to play a critical role, particularly the amount used. As with the production of concrete from cement the strength of the product increases when less water is used to make a product.
The hydration reaction itself now tends to consume a different amount of water. When adding RoadCem it is also possible to use salt water and achieve a good end result.
The empty space (porosity) is still determined by the water to cement ratio but is affected to a lesser extent as a result of the increased rate and extent of the crystallization process.
The relationship between the water to cement ratio and strength remains similar to the one shown earlier but the slope of the relationship changes and does so differently for different segments of the graph.
The extended crystallization process changes significantly when using RoadCem. The binding mechanism changes from “glue” to “wrapping” as shown below.
Simulated expressions of the hydration reactions and associated “wrapping” crystallization effect.
The “wrapping” effect associated with the crystalline products of the hydration reactions, which continue with time are in effect also responsible for the ability of RoadCem modified cement to bind even heavy clays. With cement alone this cannot be done successfully.
The same is true for the binding of other previously non bondable materials such as sludge and different waste streams.
In addition to the above, due to the composition of RoadCem, other processes also occur simultaneously and especially with clays and similar materials mainly through cat ion and anion exchange and replacement and charge neutralization as indicated in below.
Replacement and charge neutralization
Ion substitution and Charge modification for improved binding of charged particles and increased cat ion exchange capacity also result. Electrochemistry change is induced by addition of RoadCem.
This makes it possible to bind different materials even in acidic environments and when combined with the “wrapping effect” this leads to a product which has superior characteristics and performance in accord with the requirements.
Using an electron microscope one can see the structure of the material once the physic chemical and mineralogical processes have completed. Showing the structure of basic materials and a typical structure and the end products with cement alone and with cement and RoadCem added.
Electron Micrograph of different basic materials.
Photo A shows that towards then end of hydration some crystalline structures can begin to form in a cement only mixture. The second photo B clearly shows the extended crystalline structure formations that adding Roadcem to cement even in small quantities will create.
Encapsulation or “Wrapping” and Auxiliary Effects
In daily life we use many materials which are made from bound, harmful substances. For instance, a lead crystal glass with high lead content.
When such a glass is used or when a glass breaks the lead is not released because the lead particles are enclosed in the crystalline structure – they are “wrapped” in the crystal fibres.
In a similar manner RoadCem and other PowerCem Technology products are capable of encapsulation of dangerous and toxic substances and keeping the contaminated substances out of the environment as well as preventing their release into the environment.
The “wrapping” and encapsulation of polluting substances into crystalline structure which is a productvof hydration reactions of RoadCem improved cement creates a strong and stable material which has structural qualities that we desire in road construction, i.e., high compressive strength, high flexural strength, high breaking strength and high impact strength
Sludge mixed with PowerCem based product forms an unbreakable slab.
The water in the sludge has been bound in such a way that even at 2000ºC the water does not form a gas. With concrete (B25) at a temperature of 400ºC the mixture forms gas and the concrete explodes. To prove what we mean have a look at this short video demonstration.
Photo shows the lack of water penetration of the soil cement and Roadcem sample after being immersed in water for a period of 21 days.
The above examples show that adding RoadCem results in a higher resistance against external forces and temperatures that may damage the product. It also protects against attack from de-icing salts, acids, hydro carbons and other bases.
When the RoadCem product is well compacted and cured it then becomes water impermeable and no damage can occur from a freeze-thaw cycle.
For example it has survived without damage from sub-zero temperatures during the coldest of Russian winters.
This explains why it is approved by the Russian highways authority for use in Siberia.
