Preparation of Nano Silica particles by laboratory from Iraqi sand and added it to concrete to improve hardness specifications
Authors: Shnaihej Kareem Th. , Khaleel Shatha F. , Sukkar Dr. Khalid A. 
Published: May 2021

Concrete is the most common material used for construction purposes as well as in the lining of oil wells. In this work, the concrete specifications are improved through the preparation of Nano silica particles (SiO2) by laboratory from Iraqi sand and added to the concrete, which gives results with a large gap in the test of compressive strength after the addition of silica nanoparticles prepared to the concrete mixtures compared to the same mixtures without the addition of silica, to give high hardness and great capacity for bearing of compressive strength as well as increase the resistance to water penetration during the concrete structure and especially the padded cement for the oil well. In this research, Nano silica particles are prepared from the Iraqi sands available in large quantities in the cities of Iraq. The two types of sand are used: the first one is the sand of the Akheider area in Karbala province and the second is the sand of the western region in Anbar province.  The Nano silica particles have been prepared in two ways:  chemical and physical methods (milling method).

The specifications of the prepared materials are measured by several diagnostic devices, including the scanning electron microscope (SEM), the particle size analyzer apparatus, the X-ray diffraction (XRD) and the infrared spectrometer (FTIR). The results of this project proves the possibility of producing Nano silica particles with high purity and excellent specifications, which can be invested for the commercial purposes in the future.

In this research, two types of cement are used. The first is class G cement used for lining the oil wells, and the second is the Iraqi cement resistant (Portland cement) (Tasuloga Company / Sulaymaniyah province) used in the building construction.   The prepared Nano silica is added to the cement at rates ranging from 0.25, 0.5, 1 and 2% by weight, with fixed of cement amount, water, and mixed the mixture well by standard mixing machine and poured into mold cubes (5 x 5 x 5 cm) according to US specifications.

In the concrete that used of the buildings construction, it is conducted a mixture of cement and normal sand (to both of two types of sands) and added the prepared Nano silica by a percentage ratio, and poured into a cubic templates, then conducting the tests of compressive strength which is of great importance in determining the strength of prepared concrete.

The results indicates that the hardness of the concrete containing Nano materials is significantly increased and reached a level exceeding 4000 PSIG when adding 1% of the silica nanoparticles to the cement used.

On the other hand, the results shows that the Nano materials in the concrete because of their high surface area reduced the permeability of the water into the concrete structure because these substances are hydrophobic, which reduces the permeability of sulfate ions and salts, which prolong the life of the concrete for long periods of time especially in wells Oil, so this research is of great economic importance in the investment of Iraqi wealth for the production of new engineering materials