The supply of Fly Ash fit for use in structural concrete is getting problematic. There is only very little ash available meeting the criteria of the Indian and international Standards without processing raw fly ash. The processing capacity in Maharashtra is limited to two plants. Traders are tempted to claim that they have such usable material available. But the fact is they only have very small volumes which are several times oversold. It is high time that deceptive supply methods are explained to the innocent user.
As not sufficient ash of the right quality is available bulkers are filled with some suitable ash at the bottom of the bulker and as the last material at the top. The main volume in the middle of the tank is ash which does not meet the standards. Normally users take samples from the top or from the bottom outlet. They find that the material is ok, but are astonished when they get strange concrete results. This is possible as most traders load bulkers in the open, using Hydra cranes, lifting big bags to the top dome(s) of the bulker and discharge them into the vehicle.
A typical photo from such operation near the Nashik POZZOCRETE plant is demonstrating this.
This results into a number of severe problems: Already in 1987 the Indian authorities banned the use of Fly Ash following a collapse of a structure citing non existent quality control of the ash. This resulted into a 15 year set-back regarding the use of Fly Ash in structural concrete and has cost India some billion Dollars which could have been saved by using Fly Ash with OPC either as PPC or by separate mixing (site- or Readymix). Poor concrete resulting from wrong Fly Ash results into expensive repair of concrete. As 50% of all cement in India is used for public projects, this again is a cost to the Indian Nation.
Very shortly the next POZZOCRETE NEWS-letter will be circulated. This issue will focus on sampling methods and standards and provides help by selecting the right tools to extract representative samples from bulkers. If you are not already receiving this newsletter you can subscribe via the CONTACT section of this web-page.
In respect to POZZOCRETE bulker supply please check:
1) all bulker inlets and outlets are sealed with DIRK seal
2) the driver carries a test certificate in accordance with the ISI quality verification procedures
3) the transport documents clearly prove that the bulker had been loaded at the Nashik POZZOCRETE plant (dispatch details can be accessed via the customer section of this web-site using customers log-in and password.