NanoGrout
F e a t u r e
Hassle free Post-Tension
Cable Duct Grouting
ost-tensioned concrete is being
used for many decades around the
world in a variety of construction
projects like bridges, buildings,
tanks, silos, parking structures,
seismic walls etc. Post-tensioned structures
offer numerous advantages including
reduced dead load and member depth. In
addition to this, post tensioning also allows
for increased span-to-depth ratio.
One of the main reasons for increasing
use of post-tensioning systems is the
advancement of technology in recent years.
Older post-tensioning systems were mainly focusing on obtaining the desired pre-stress
force and not on durability, which is the prime reason of many
project failures.
It was apparent that some of the tendon corrosion protec-
tion systems used could not adequately protect tendons in the
most aggressive environments. With the development in tech-
nology and improved work practice, durability aspects are being
considered very seriously in recent systems. A new concept of
multi layer protection of structures has been created; this
includes design of the structure, waterproofing membranes in
case of critical surfaces exposed to water, dense concrete with
minimum permeability, leak tight encapsulation of tendons and
most importantly, protection of pre-stressing steel with cemen-
titious grout.
New specifications are being designed and modified to
address the corrosion problems. Cementitious grout is the key
element of the overall corrosion protection which provides excel-
lent shield for the pre-stressing steel. The principle objectives of
grouting are to protect the pre-stressing steel from corrosion by
encasing it in a passive environment and filling the duct to mini-
mize voids in the complete structure.
The specifications of cement grouts used in the past for
post-tensioning tendons were not stringent enough in terms of acceptance criteria. And other test methods which
were being used were not resourceful to detect poor performance of a particular grout mix.
pecifications for cementitious grouts have
changed over the years and new specifications
issued by Post-T ensioning Institute (PTI) and other
international standards like European S tandards,
EN 445, 447 have introduced test methods that are
in line with the actual conditions at site. For exam-
ple, the 'Wick Induced T est' requires an actual
strand to be inserted into the grout during testing of
bleeding and volume change which is similar to the
condition at site.
Benefits of using factory mixed grout Important technical properties of the grout used for post tensioning are Flow ability - to ensure complete filling of the tendon ducts, Volume change - for positive expansion to complete-ly fill the tendon ducts, Bleeding - to limit free water inside the tendon duct, and to reabsorb any bleed water within the specific time and Strength - to provide indication of the grout quality with respect to its bond and shear strength. The constituents of cement grouts have complex interactions particularly when it comes to admixture and cement compatibilities The traditional practice of post-tension grouting involves mixing of cement, additives and water at site just before grouting opera-tions. This may lead to considerable incon-sistencies in properties of grouts due to any variance in cement with respect to source, type, specific surface,
age and contents like chloride & tri-calcium aluminates, in spite of using a single source of admixture.The best way to ensure durability of the grout used to protect the tendons is by applying the fac-tory mixed ready to use grout material, where only water needs to be added at site. This avoids vari-ous inconsistencies and operational problems that may occur if the constituents are mixed at site,thereby guaranteeing reliable performance.A perfect solution NanoGrout CFG
is factory controlled, pre-mixed, non-shrink cable flow grout for the post-ten-sion ducts and sonic tubes. This product has attained Dubai Municipality Technical Approval which is a hallmark of stringent quality norms which reflects the supreme quality management system at Conmix. This product has found integral use in the construction of Burj Khalifa, Atlantis Hotel,Dubai Airport and other prestigious projects in the U.A.E. NanoGrout CFG complies with BSEN 445 &447 standards for post tension cable duct grouting.It is the perfect answer to a long standing search of pre-stressing companies and consultants to have a hassle free grout based on "just add water" technique.CONMIX Construction Chemicals division manufactures a comprehensive range of repair products, floorings, non-shrink grouts, waterproofing, sealants, curing compounds, admixtures,mould release agents, bonding agents, tile adhesives and tile grouts. The company follows a quality management system cer-tified to ISO 9001, maintaining quality assurance in design,development, production, installation and service. Conmix prod-ucts comply with all international standards and are used in more than 32 countries. Supported by modern and substantial manufacturing units, well equipped R&D facility, state of art lab-
oratories, experienced qualified engineers, competent technical
support department and proactive sales team, CONMIX is an ideal partner for all construction needs.(Communication by the management of the company)P
CONMIX has introduced a new method of cable flow grouting with 'Just Add Water' Technique.
Post Tensioned Concrete Slab
NanoGrout CFG with ZERO BLEED in Wick Induced Test xxx Construction World May 2010Wick induced
test