February 12, 2008

Microsilex is a product based on natural silica with pozzolanic properties which can improve performance and durability concrete and mortar manufactured with Portland Cement.


Microsilex is light brown in color and adding this product does not affect the final concrete color. Besides, it is compatible when adding iron oxide based pigments for concretes with integrated color.

Uses and applications:

Microsilex must be used as an additive in proportion with the cement weight in concrete or mortar mixes. It may be used as an additive for cement or as a cement substitute. In concrete mixes it can be used in constructions such as: pavement, ducts, bridges, residual water tanks, etc.


When used in concrete mixes, Microsilex increases the resistance in the later stages (from 28 days on). It improves shapeability, reduces permeability, increases sulphate resistance, helps to control the alkali-aggregate reaction and increases concrete abrasion resistance.

Physical and chemical characteristics:

Chemical properties   ASTM C-618  Microsilex
SiO 2 + Al2O 3 + Fe 2O 3 (%) 70.0 minimum  91.30
SO 2 (%) 4.0 maximum  0.14
Humidity (%) 3.0 maximum  1.25
Loss due to ignition (%) 10.0 maximum 0.38
Alkalis such as (%) 1.5 maximum  0.05

Physical properties    ASTM Microsilex
Fineness when sifted through a  No 325 (45 um) mesh pass. %

 ASTM C-430
76.0 minimum 

Resistance to sulphates up to 180 days (%)  ASTM C-1012
0.05 maximum 
Alkali-silica reaction up to 180 days (%) ASTM C-227
0.05 maximum 
Density gr/cm 3 ASTM C-188 
Does not apply 
Amount of water required (control %)
ASTM C-311
115 maximum 
Pozzolanic activity index up to 7 days (control %)  ASTM C-311
75 minimum
Pozzolanic activity index up to 28 days (control %)  ASTM C-311
75 minimum
Expansion in mortar up to 14 days (%) ASTM C-1260
0.1 maximum

Recommendations for use:

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