CEMENTING MATERIAL FROM CALCIUM CARBIDE RESIDUE - RICE HUSK ASH Kumar Amit VIII Sem. B.E., (CIVIL Engineering) Department of Civil Engineering Sir MVIT,Bangalore 1. INTRODUCTION : Calcium Carbide Residue (CCR) is a by-product of acetylene production process (John, 1993), and its production is described in the following equation: CaC 2 +2H 2 O→ C 2 H 2 +Ca(OH) 2 ---------------------------------------- (1) CCR consists mainly of calcium hydroxide, Ca (OH) 2 , and is obtained in a slurry form. From Eqn.1, it is seen that 64 g of calcium carbide (CaC 2 ) provides 26 g of acetylene gas (C 2 H 2 ) and 74 g of CCR in terms of Ca (OH) 2 . Due to its high base, calcium carbide residue was hardly utilized in any work and all of it went to a disposal area as slurry form as shown in Fig. 1(a) 1
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CEMENTING MATERIAL FROM CALCIUM CARBIDERESIDUE - RICE HUSK ASH
Kumar Amit VIII Sem. B.E., (CIVIL Engineering)
Department of Civil EngineeringSir MVIT,Bangalore
1. INTRODUCTION :
Calcium Carbide Residue (CCR) is a by-product of acetylene production process (John, 1993),
and its production is described in the following equation:
CCR consists mainly of calcium hydroxide, Ca (OH) 2, and is obtained in a slurry form. From
Eqn.1, it is seen that 64 g of calcium carbide (CaC2) provides 26 g of acetylene gas (C2H2) and
74 g of CCR in terms of Ca (OH) 2. Due to its high base, calcium carbide residue was hardly
utilized in any work and all of it went to a disposal area as slurry form as shown in Fig. 1(a)
After being sundries for a few days, the slurry form of calcium carbide residue is changed to
dry form, as shown in Fig. 1(b) Rice Husk Ash (RHA) is derived from the burning of rice husk,
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which is the by-product of rice milling. It was estimated that 1,000 kg of rice grain produced
200 kg of rice husk, after rice husk was burnt, about 20% of the rice husk or 40 kg would
become RHA (Mehta 1986). RHA contains a high amount of SiO2, most of which is in
amorphous form (Gambhir, 1995; Mehta, 1986) which makes RHA a pozzolanic material
according to ASTM C 618 (1997d). Pozzolana as defined by ASTM C 618 (1997d) is a material,
which is siliceous, or siliceous and aluminous material by composition. In general, pozzolana
has little or no cementing property, however when pozzolana has high fineness and in the
presence of moisture, it can react with Ca (OH) 2 at room temperature to provide
property. Upon the cement hydration, the main products are calcium silicate hydrate (CSH),
calcium aluminates hydrate (CAH), and calcium hydroxide, Ca (OH) 2. CSH and CAH are the
cementations materials in the mixture and contribute to the strength of concrete. However,
CSH produces much higher compressive strength than that of CAH, while Ca(OH)2 can react
with SiO2 and Al2O3 from pozzolanic material resulting in additional CSH and CAH in the
mixture, improving some of the properties of the concrete (ACI 232.2R 2000). These improved
properties include increased acid resistance, reduced bleeding, increased compressive strength,
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reduced permeability, etc. (Krammart, et al., 1996) used 30% of CCR and 70% of fly ash by
weight as cementations material of mortar and obtained compressive strengths of 20.9MPa at
90 days. It is believed CCR which is rich in Ca (OH) 2 and RHA which has high SiO2 can react
together by the pozzolanic reaction, resulting in products that would be similar to those
obtained from cement hydration process. Therefore, the objective of this research is to utilize
two waste materials as a new cementing material to substitute Portland cement. In addition,
the utilization of the two materials will reduce the production of Portland cement as well
as reduce the waste disposal volume to make a better environment.
Fig.1 Disposal area of slurry and dry forms of calcium carbide residue: (a) slurry form and (b) dry form
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2. EXPERIMENTAL PROGRAM :
2.1 Materials
Materials used in this experimental program consisted of calcium carbide residue assigned as
CCR, rice husk ash (assigned as RHA), Portland cement Type I, river sand which was passed
sieve No. 16 and retained on sieve No. 100, water, and superplasticizer Type F (naphthalene
base). CCR was collected from the disposal area in the dry form, as shown in Fig.1 (b), and was
sun-dried for 2–3 days to reduce its high moisture content. After sun-dried, the CCR had a
moisture content less than 3% and was then ground by a Los Angeles abrasion machine until
the particles retained on sieve No. 325 less than 10% by weight. Rice husk was collected from
rice mill in Pathumthani province, Thailand, and was burnt to produce in fibrocement
incinerator at approximately 600 to 800°C (Alex, 1981). The RHA was then ground by a Los
Angeles abrasion machine until the particles were as small as those of CCR, i.e., retained on
sieve No. 325 less than 10% by weight.
2.2 PROPERTY OF MATERIALS
Chemical compositions of CCR, RHA, and Portland cement Type I was analyzed by x-ray
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fluorescence spectrometer. Physical properties such as specific gravity, Blaine fineness, material
retained on sieve No. 325, and particle shape of the materials by Scanning electron microscope
were also investigated.
2.3 PROPERTY OF PASTE
Normal consistency and setting times of CCR-RHA pastes were investigated in accordance
With ASTM C 187 (1997b) And ASTM C 191 (1997c), respectively, and compared to those of
Portland cement paste. The ratios of CCR: RHA were varied as 20:80, 35:65, 50:50, 65:35, and
80:20 by weight.
2.4 MIX PROPORTION AND TESTING COMPRESSIVE STRENGTH OF MORTAR:
In this study, the control or standard mortar was a mixture using Portland cement Type I as
cementations material. The rest of the mortars were used as a mixture of CCR and RHA as
cementations material. The mortar contained 1.0 part of cementations material to 2.75 parts
of river sand by weight. The water-cementations material ratio (W/C) was kept at a constant
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of 0.65 in all mixtures. Superplasticizer was employed in order to maintain the flow of mortar
between 110+or-5 since the mixture of CCR-RHA mortars required more water to achieve the
target flow. Table1 gives the mix proportions of all mortars and it is noted that the control mortar has W/C of 0.65 to produce flow of 114 without the adding of superplasticizer. The
procedure to prepare mortar from a new cementing material was the same manner as to
prepare the control mortar. Mortars cube of 5 cm were cast and removed from the molds
after 24 h, then cured in water until the date of testing. Compressive strengths of mortars were
determined at the age of 1, 3, 7, 14, 28, 60, 90, and 180 days of curing.
Table1 Mix proportions of mortar containing a new cementations material (CCR+HRA)
Mortar Calcium
CarbideResidue
RiceHusk ash
Cement Sand Water Superplasticize
Flow
Control 20C80R 35C65R 50C50R 65C35R 80C20R
—2035506580
—8065503520
100—————
275275275275275
656565656565
—5.884.013.893.251.75
114107108113108110
Note: Numbers 20, 35, 50, 65, and 85 in front of the capital C and R mean percentage of
calcium carbide residue and rice husk ash in the mortar mixture, respectively. For example,
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35C65R means mortar containing 35% of calcium carbide residue and 65% of rice husk ash by
weight as cementations material. ‘‘Control’’ means standard mortar.
Table 2: Chemical Compositions of Calcium Carbide Residue, Rice Husk Ash, and Portland cement Type I
Material Chemical composition (%) SiO2 Al2O3 Fe2O3 CaO MgO Na2O K2O SO3 LOI