METHODS FOR STRENGTHENING OF ADHESION BONDS BETWEEN SURFACE OF USED MOLDING SAND AND ORGANIC BINDER WHILE OBTAINING ACTIVATED MINERAL POWDERS

• Main Author: Ya. N. Kovalev
• Format: Article
• Language: Russian
• Published: Belarusian National Technical University 2016-12-01
• Series: Nauka i Tehnika
• Subjects: used molding sand; hydrofobisation; activated mineral powder; asphalt concrete
• Online Access: https://sat.bntu.by/jour/article/view/957

Value of adhesion bond between mineral surface of acid quartz materials and organic binder (bitumen) has a great significance while forming structure of asphalt concrete strengthening. It has been established theoretically and experimentally that that the bond is insignificant and it causes premature destruction of structure for asphalt-binding substance and finally asphalt concrete. In this connection the relevant objective of the paper is a search for efficient methods for strengthening of adhesion bonds between the indicated structural components. A development for obtaining mineral powders from used molding sand activated by various hydrofobisation methods plays rather important role in that matter. The development of several methods for obtainment of activated mineral powders from used molding sand and also know-how pertaining to behavior of asphalt concrete formed on their basis have made it possible to create rational technologies which are applicable under operational conditions of the specified asphalt concrete plants in any region. The executed investigations on hydrofobisation of particles surface for the used molding sand with the help of sodium alkyl siliconates have established the basis for development of new efficient method for obtaining activated mineral powders from the used molding sand. The method presupposes treatment of the used molding sand in the process of mill flow in a ball drum while using sodium ethyl siliconate (0.3–0.7 % as compared with the mass of mineral raw material). Juvenile particle surface of fresh milled powder from the used molding sand has a maximum activity among the known filling compounds in relation to althin and this phenomenon can be explained by additional structure-forming impact of chemically active organic foundry binding agents which are contained in the used molding sand. That particular property allows to use widely powder from the used molding sand which contains uncured althin as a polymer component.