Inadequate protection against corrosion offered by normal grouts is due to:

a.) Excessive capillary micro porosity due to high water/cement ratio. Using NEOGROUT FAC100 the water/cement ratio is reduced to 0.3

b.) High macro porosity caused by bleed water collecting under strands and in the upper part of the sheath. When bleed water evaporates and is reabsorbed by the cement paste, voids form thus providing easy access for corrosive substances.
With the use of NEOGROUT FAC100, the volume of bleed water is considerably lower: it ranges from 0 to a maximum of 2% depending upon the type of cement used.

c.) Shrinkage of cement paste and consequent cracking. With normal cement grouts final shrinkage varies from 2 to 3mm. NEOGROUT FAC100 allows not only shrinkage to be eliminated completely, but also slight expansion to occur during setting and hardening.

The main properties of grouts containing4- 6% of NEOGROUT FAC100, can be summed up as follows:

Very high flowability (as measured by the Flow Cone Test) without bleed water or with a very low amount of it. The pumpability of the grout is assured for at least two hours at + 20°C.
High mix water retention. This very important property imparts high cohesion to the very flowable mix. Under vacuum, of 600 mm Hg, over 90% of the water is retained by the NEOGROUT FAC100. Inadequate water retention would allow water to separate from solid components when the grout is forced through strands of tendons.
Absence of shrinkage, and expansion ranging from 200 to 800 μm/m depending upon the type of cement used.
Initial setting time in excess of 3 hours at +30°C.
High early and ultimate strengths: depending on the type of Portland cement used, strengths can range from 20 to 40 N/mm² at 1 day and from 50 to 70 N/mm² at 28 days. Slightly lower values are obtained if pozzolanic or slag cements are used.
High bond to steel: after 7 days the value is in excess of 15 N/mm².

Owing to its high flowability, a cement grout made with4- 6% by weight of NEOGROUT FAC100 assures the complete filling of sheaths, especially among the strands of cables. This ensures maximum protection of steel against corrosion caused by aggressive agents. As this high flowability is obtained with a low water / cement ratio, the hardened cement paste is dense, compact, impermeable and, therefore, highly durable. On the other hand, the high cohesion and fluidity of the fresh mix, together with freedom from shrinkage, prevents the formation of voids which are often responsible for the penetration of aggressive agents.