چكيده به لاتين
With the development of nano technology, the production of nano sized materials has been facilitated and their use in the sciences related to concrete technology and cement compounds has faced an increasing expansion. Therefore studying the possibility of using new nano materials can lead into new research fields.
Among different types of nano materials, two dimensional nano plates are used in a variety of cementitious products due to their special mechanical properties. The most famous of these materials is the family of graphene and graphene oxide, which despite improving the final product, due to instant agglomeration in ionic environments, their use in cementitious products is associated with inevitable difficulties. For this reason, the introduction of alternative nanosheets from the group of layered materials can create a new chapter in the application of nano materials compatible with cement products.
In the group of layered materials, the transition metal dichalcogenides are widely used and preferred over other groups because of their behavior and the special mechanical properties they have and can add to the final product. One of the compounds of this group is molybdenum disulfide, which is widely used in electronic, optic, aerospace and other industries.
However, considering that there is no history of it's use in the construction industry and cement compounds or even alkaline aqueous matrices similar to cement paste, therefore, in order to check the possibility of using it together with cementitious products, first and above all, the stability of dispersion of these nano sheets in simulated alkaline aqueous matrices must be investigated.
For this purpose, in the present study, an optimized base solution of nano sheets dispersed in pure water was prepared. Then it's stability in environments containing chloride salts of sodium, potassium, and calcium as well as corresponding hydroxides of sodium, potassium, calcium and finally the pore solution was compared and studied.
Also, scanning and transmission electron microscopic photos (SEM and AFM), along with special tests and examinations like Ultra-Violette visible spectrometer (UV-VIS), XRF and XRD, FTIR and zeta potential were used to check the dispersion, stability and behavior of these nano sheets in neutral and alkaline aqueous environments.
And finally, some preliminary experiments were conducted regarding the use of compatible surfactants with cement paste, such as polycarboxylate ether-based super lubricant, naphthalene-based super lubricant, gum Arabic and sodium dodecyl sulfate.
