Page 9 - Open-Access-Oct-2019

TECHNICAL PAPER 1948

EffEct Of ElEvAtED

tEMPErAtUrEs On

fErrOchrOME Ash

bAsED MOrtArs ChEThAn KumAR B.,

SuBhASh C. YARAgAL, B.B. DAS

Abstract reducing CO emissions and waste disposal problems [2-7] . Benefit
2
of SCM and their consequences with alternative materials has
Due to boom in construction sector, large amount of Ordinary
Portland Cement (OPC) is being consumed. Cement production been broadly deliberated by many researchers. Further, usage of
is energy intensive and releases large amount of CO into SCM can be one possible way to reduce the effect of elevated
2 temperatures. SCM such as, fly ash (FA), ground granulated
atmosphere. Efforts are on to bring down cement consumption
by the use of secondary cementitious materials. An attempt is blast furnace slag (GGBS), etc., consumes Ca(OH) by means
2
made to study the influence of combined effect of various levels of secondary pozzolanic reaction by generation of additional
[3, 6-8]
of ferrochrome ash (FCA) and lime, as replacement to OPC for C-S-H gel . The generation of additional C-S-H gel increases
different cement mortar mixtures at elevated temperatures. FCA the mechanical properties, which further reduces the effect
replacement considered is in the range of 0% to 20% and along of elevated temperature on residual compressive strength
with 7% lime as replacement to cement. Compressive strength retention of cementitious materials.
of cementitious materials is being an important parameter in Ferrochrome ash (FCA) is an industrial by-product obtained from
the design of structures. The main objective of this work is to ferrochrome alloy production. Since FCA substances contain
assess the residual compressive strengths at different levels alumina silicate just as in FA, it can be used as SCM, which
of temperatures (200, 400, 600, and 800ºC) for a retention reduces the environmental impact associated with production
period of half an hour. Residual strengths of mortar mixtures and usage of OPC. Acharya carried out detailed study on the
[9]
produced, using FCA, have shown a good performance. use of FCA as cementitious materials. Results showed excellent
Upto 20% FCA and 7% lime, mixture turns out to be a good performance under severe environmental conditions, such as
elevated temperatures enduring material. This would increase sulphate attack, acid attack, and abrasion resistance.
the suggested application for environmental friendly materials.
Important differences were seen in microstructural observations Inspite of good performance of FCA as SCM, it is clear from
with scanning electron microscope (SEM) for various levels of the literature that limited research works were published on the
FCA and lime incorporated mortars.
effect of elevated temperatures on FCA based cementitious
Keywords: Elevated temperature, Ferrochrome ash, Residual materials. Therefore, in order to address this knowledge gap,
strength, Scanning electron microscope, X-ray diffraction. residual compressive strength of FCA based mortars subjected
to elevated temperatures is investigated. X-ray diffraction
1. INtRODUCtION (XRD) analysis was used to observe mineralogical changes with
Elevated temperatures, due to the accidental event of fire, addition of FCA as replacement to OPC. Scanning Electron
causes severe strength loss in cement based materials. This may Microscope (SEM) has been used to observe microstructural
reduces the service life of structure that it was intended to be changes of FCA-based mortar mixtures under elevated
performed. Effect of elevated temperatures on cementitious temperatures.
materials is dependent on several factors, such as : cement,
aggregate, microstructure and its mineralogical composition. 2. MAteRIALs AND eXPeRIMeNtAL
Yaragal et al have reported severe loss in compressive strength PROgRAM
[1]
at 800ºC for a retention period of 2 hours. Residual compressive 2.1 Cement
strength was found to be only 18% in case of normal strength
concretes. Ordinary Portland Cement (OPC) of 53-grade that confirming
to is used. Chemical oxide composition of OPC is presented in
[10]
In recent years, supplementary cementitious materials (SCM) Table 1. Physical properties like specific gravity, Blaine’s specific
are being utilized and there by reducing the usage of Ordinary surface area, initial and final setting times were 3.1, 345 m /kg,
2
Portland Cement (OPC) indirectly addressing issues such as : 65 minutes and 215 minutes, respectively.

14 The IndIan ConCreTe Journal | oCToBer 2019