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1. Introduction
The construction industry is one of the oldest activities ever known
and since the dawn of humanity it was performed by hand, gener-
ating as sub-product a large amount of waste of various natures.
It is also responsible for the excessive consumption of natural re-
sources from non-renewable sources (Boldrin et al. [1]).
However this is one of the sectors that has great potential to ab-
sorb the waste. The recycling of construction waste as aggre-
gates is an important alternative for reducing the environmental
impact and for its preservation (Oliveira et al. [2], and Helene
Levy [3], John [4]).
The use of construction and demolition waste in the manufacture
of concrete blocks and mortar settlement is technically feasible
and can be used in the construction of popular housing (Farias et
al. [5]). Bastos et al. [6] also emphasize the use of CDW for paving
new roads.
According to Ajdukiewicz and Kliszczewics [7] after recycling
waste coming from the reconstruction of roads and bridges made
of reinforced concrete and prestressed, they are used as aggre-
gates in Eastern Europe.
In conformity to studies by Butler et al. [8] on building blocks of
concrete with recycled aggregates it can be noted that the blocks
with recycled aggregates had lower levels of density and higher
rates of absorption and voids compared to values obtained by the
reference blocks.
Fonseca Junior and [9] noted that recycled aggregates with maxi-
mum dimension less than 9.5 mm can be used not only in concrete
with plastic consistency, but in concrete artefacts with zero abate-
ment and good resistance, as well as low consumption of cement.
According to Boldrin et al. [1] increasing substitution of natural ag-
gregates by recycled aggregates from construction, employed in
the manufacture of concrete blocks, affects the consistency of the
mixtures, with a decrease in fluidity. The fine recycled aggregate
had higher water absorption than the traditional fine aggregate,
affecting directly the mechanical properties of concretes. Concrete
with percentages up to 60% of construction waste seems to be
most suited for use in the manufacture of concrete blocks.
According to Dafico et al. [10] the concrete blocks produced with
recycled construction aggregates have a very large variability con-
cerning the results of compression strength; however it was ob-
served that the best mixture is when the cement is mixed with the
aggregate in dry saturated surface, followed by the introduction of
mixing water with air-incorporating additives.
Resolution no 307 of CONAMA (National Council of Environment)
establishes guidelines, criteria and procedures for the manage-
ment of construction waste in order to provide social, economic
and environmental benefits. On August 16, 2004, Resolution no
348 of CONAMA amended art. 3, item IV, of CONAMA Resolu-
tion no 307.
Considering that such wastes represent a significant percentage
of solid waste generated in urban areas and that the disposal of
construction waste in inappropriate places contributes to the deg-
radation of environmental quality, the municipalities are respon-
sible for the environmentally sound management and disposal of
such wastes seeking effective reduction of environmental impacts.
According to Resolutions no 307 and no 348 construction waste
are classified into four classes:
I - Class A – reusable or recyclable waste like aggregates, such as:
a) from construction, demolition, renovations and paving repairs
and other infrastructure works, including soil from earthworks;
b) from construction, demolition, renovations and repairs of
buildings: ceramic components (bricks, blocks, tiles, flooring
boards, etc..), mortar and concrete;
c) from manufacturing process and / or demolition of pre-cast
concrete (blocks, pipes, curbs, etc..) produced in construction
sites;
II - Class B - recyclable waste to other destinations, such as plas-
tics, paper / cardboard, metal, glass, wood and others;
III - Class C - wastes for which no economically feasible technolo-
gies or applications have been developed that enable recycling /
recovery, such as products from the cast;
IV - Class D - hazardous waste from the construction process,
such as paints, solvents, oils and other contaminated or those
harmful to health coming from demolition, renovations and repairs
of radiology clinics, and other industrial facilities as well as tiles and
other objects and materials containing asbestos or other products
harmful to health .
In Brazil, recycling companies separate the contaminants such as
wood, plastics and nonferrous metals from the construction waste,
by hand. Usually the recycled aggregate is used as basis for con-
struction paving and sealing concrete blocks. Countries like Ja-
pan, England and Holland partially or completely replace natural
aggregates by recycled ones, due to higher levels of contaminants
removal of construction waste (Angulo and John [11]).
1.1 Agreement
In this work we analyzed the incorporation of construction and de-
molition waste (CDW) in concrete used in the manufacture of hol-
low blocks of plain concrete masonry units. The aim of this study
was to evaluate the influence of increasing substitution of CDW
by mass of natural aggregates in the mixture of concrete, the me-
chanical properties of concrete blocks according to the specifica-
tions of Brazilian standards.
2. Materials and experimental program
All materials used in the experimental part of the research were
provided by the companies in the metropolitan region of Campi-
nas, such as CPV-ARI Portland cement, sand of quartz origin, ba-
saltic gravel and recycled construction waste as aggregates.
At the recycling plant, CDW passed through a screening process
to remove impurities such as iron, rubber, plastic and organic ma-
terial [Figure 1], before being crushed and separated into different
particle size. Figures 2 and 3 show the fine and coarse recycled
aggregates respectively, used in this research.
The CDW chosen to be used was that material coming from waste
cement composites (mortars and concretes) called “gray.”
Physical Aggregates Characterization
Tests of physical characterizationof aggregatesweredone, suchas: de-
termining the density according to the specifications of NBRNM52:2009
[12] for fine aggregates and NBRNM53:2009 [13] for the coarse aggre-
gates, determination of bulk density of the aggregates as specifications
in NBRNM45:2006 [14], and classification of aggregates according to
167
IBRACON Structures and Materials Journal • 2012 • vol. 5 • nº 2
R. C. C. Lintz | A. E. P. G. A. Jacintho | L. L. Pimentel | L. A. Gachet-Barbosa