چكيده به لاتين
The use of recycled materials obtained from construction debris in the construction
industry has become one of the main goals of researchers in the world today to
prevent environmental damage and to realize the concept of sustainable
development. One of the most widely used materials in the construction industry,
in which construction waste can be used as aggregate, is concrete. But concrete
made from this model of aggregates often has lower quality than concrete with
natural aggregates. The main weakness of this type of concrete is in the transition
zone of concrete made with these aggregates. To compensate for this weakness,
there are various methods available. In this research, the method of pre-soaking
aggregates in several types of pozzolanic solutions, including micro silica, micro
zeolite, nano silica, and nano montmorillonite, was used to investigate the effect
of this method on mechanical properties, including strength. compressive and
modulus of elasticity and durable properties of concrete made, including shrinkage
due to drying, resistance to sulfate attack, corrosion potential of rebar (half pile)
and electrical resistance. In this research, all the concretes made from recycled
aggregates were coated with pozzolans for 24 hours with a factor of 200 times the
specific surface area of the aggregates. By coating the aggregates, pozzolanic
materials improved the transition zone and reduced the weaknesses of this type of
concrete. The results showed that in the discussion of mechanical properties,
compressive strength in 28 days, all pozzolanic solutions, except for micro zeolite
solution, improved the compressive strength, and the greatest increase was related
to concrete with aggregates pre-soaked in nano silica solution with a 12.4%
increase in compressive strength. Also, concrete with recycled aggregates presoaked in micro zeolite solution experienced a 5%decrease in compressive strength
in 28 days. In 91 days, all the concretes faced an increase in compressive strength,
so that the highest amount was related to the concrete with pre-soaked nano
montmorillonite recycled aggregates with an increase of 29%. Also, the results of
the modulus of elasticity test showed that in 28 days, the highest increase was
related to concrete with aggregates pre-soaked in nano silica solution with an
increase of 10.4% and in 91 days, it was related to concrete with aggregates
pre-soaked in nano montmorillonite solution with a 12.4% increase. Was. In
terms of durability tests such as corrosion potential (half pile) and electrical resistance, concretes with recycled aggregates pre-soaked in nano silica and micro
silica solution had the best results, respectively. Other durability tests such as
sulfate attack and long-term shrinkage are ongoing. In total, the obtained results
showed that the method used was effective and improved the mechanical and
durability properties of concrete made with this type of aggregates.
