– greenhouse gas. While increasing demand for concrete

– Ceramic waste powder dominated samples have higher water
absorption by capillary action.

– With increasing replacement of cement with ceramic waste powder,
dry bulk density decreased.

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– Strength increased due to relative pozzolanic reaction of
ceramic.

– Structure of ceramic based mortar
appears compacted than conventional concrete

-The use of ceramic waste powder in
mortars has technical and environmental advantages

 

ABSTRACT

Reuse of waste from construction and
demolition is one of the most important purposes in the world. One of the most
important wastes, due to its wide range of reuse possibilities, is ceramic
waste of (CWP) the construction and ceramic industry. The aim of this research
was to investigate some of the physical and mechanical properties of a
laboratory-produced mortar. In this paper, Portland cement type (II) was
replaced by 5, 10, 15, 20 and 25% of CWP from Almas-Kavir Company (Iran). The
mortar specimens were cured in water for 7, 14, 28 and 56 days, then properties
of fresh and hardened mortar, such as the density of fresh mortar, initial and
final setting time, the flow of hydraulic cement mortar, compressive strength,
alkali-silica reaction of aggregates, dry bulk density, ultrasonic pulse
velocity, water absorption of the hardened mortars were determined. Finally, in
order to understand the hydration mechanism of the materials as it relates to
the strength properties, microscale tests, SEM and XRD were used to examine the
fragments of the selected mortars. From the results, a mortar sample containing
10% CWP as replacements for cement, gave higher strength values than the
control and other mixes. Results also show that ASR expansions are expected to
increase with reduced CWP. Microstructural analysis of the best mix revealed
that it has lower proportions of, portlandite than the control mix, and this
could be responsible for the strength gained.

Keywords: Ceramic waste, Cement, Pozzolan, Mortar, Ettringite, Portlandite, Environment

1. Introdution

 

      Portland cement
production accounts for around 5% of the global carbon dioxide (CO2) emissions,
which is categorized as a major greenhouse gas. While increasing demand for
concrete is essential and associated with rapid global development and construction
industry growth, cement is the primary and most expensive component of concrete
mixture. Partial or full replacement of cement is considered a sustainable
solution toward decreasing the environmental impact of cement production and
will also contribute to sustainable concrete. The growth of industrial activity
also produced a large volume of solid waste that annually increases in several
industrial sectors, becoming an environmental issue its final deposition. Among
this industrial sector, the ceramic industry growths due to its high
heat-efficient envelop for building. In Europe, the amount of wastes from
different production stages of the ceramic industry reaches to 3-7 % of its
global production, meaning millions of tons of calcined-clays per year (Pavlík
and Fort et al., 2013). The same values of scrap are reported for the Iran
ceramic industry. The cement production companies have begun to implement a
series of measures to reduce their environmental impact and transform the
Portland cement into a material with sustainable development. To find economic,
technological and environmentally friendly solutions, the use of industrial
by-products or waste material has been widespread (Puertas and García-Díaz et
al., 2008) in the manufacture of Portland cement. In recent years, mortars made
with ceramic waste powder (CWP) have been investigated. Irassar et al. (2014)
studied the utilization of CWP as pozzolanic materials and reported that
incorporation of ceramic waste with Portland cement simulates hydration due to
enhancement of effective water-to-cement ratio in the system. However, it was
claimed that with replacement between 8 to 40% no pozzolan activity was
observed at early ages, while good pozzolanic activity was observed at 28 days.
Pokorny´ et al. (2014) showed that incorporation of CWP reduced compressive,
bending strength, and thermal properties while improving thermal insulation.
For similar ceramic waste, Vejmelková et al. (2014) showed that CWP slowed
compressive strength development, and the 28 days compressive strength reaching
90% of the reference concrete with no CWP. Similarly, Heidari et al. (2013) and
Pacheco-Torgal et al. (2011) reported reduction in early age compressive
strength of concrete with an increase of CWP content but with minor strength
reduction at later ages. Wang et al. (2009) showed that pozzolanic activity and
strength of concrete incorporating CWP preceded that incorporating fly ash.
However, addition of CWP reduced the heat of hydration and increased shrinkage.
The microstructure of mortars incorporating CWP demonstrated close-grained,
dense, and reticular hydration gel. In this paper, the potential of using
ceramic wastes as partial replacement of Portland cement is studied. An
experimental program examining replacing 0, 5, 10, 15, 20, and 25% of Portland
cement with CWP was developed. Mechanical and durability characteristics of
concrete were examined. Furthermore, microstructural analysis of the cement
paste mixtures incorporating CWP was performed.

2.  Materials

 

2.1. Cement

  
Ordinary Portland cement Type (II) (OPC) of Momtazan Company (Iran)
meeting the requirements of ASTM C150 (2009) was used in the preparation of
concrete mixtures. The chemical and physical properties of cement are given in
Table 1.

 

 

2.2. Ceramic waste powder

     The ceramic,
which used in this experimental work was sourced from the ceramic waste of
Rafsanjan Almas-Kavir Company (Iran). The ceramic sources are from different
manufacturers, but they are original of stoneware ceramic source. The ceramics
were washed with water in order to get rid of debris that stuck to the surface,
and subsequently, they were air-dried for a few days. Thereafter, a hammer was
used to grind the ceramic into granular sizes of 2–4.75 mm. Another portion of
the ceramics was pulverized to a powder size of 1-100 µm. The particle size
gradation for cement and CWP is shown in Fig. 1. The cement is finer than the
CWP. The oxide composition of CWP was determined using X-ray fluorescence (XRF)
and the result is presented in Table. 2. The chemical and physical properties
of CWP and cement are given in Table 2 and Table 3 respectively. Also, scanning
electron microscope (SEM) image of the CWP showed that it consisted of
irregular and angular particles that resemble the shape of cement particles and
X-Ray Diffraction (XRD) of CWP is shown in Fig 3 and Fig 4 respectively. As can
be seen in table 4, CWP has suitable conditions for an ideal pozzolan regarding
ASTM C618 (2007).

 

 

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