VolumeInternational II Number Journal 2 2011 for [23-28] Environmen tal Rehabilitation and Conservation Volume[ISSN 0975 III No. - 6272] 1 2012 [30 – 37] [ISSN 0975 - 6272] Comparative study of Eco Cement with OPC and PPC Vinay Deulkar1, Manish Verma2, Umesh Pendharkar3 Received: March 23, 2012 ⏐ Accepted: May 10, 2012 ⏐ Online: July 27, 2012 Abstract durability and rheology. This paper discusses Around 26 billion tons of CO2 are released to the atmosphere annually, around 20 billion the potential impact on sustainability of the metric Tons of which is from the burning of new eco-cement Technologies for fossil fuels and close to a significant 2 billion sustainability and comparison of physical tones from the production of Portland cement. properties of Eco Cement with Ordinary Over two tons of concrete are produced per Portland Cement (OPC) and Portland person on the planet per annum. There by pozzolana cement. It also discusses the amount causing the greenhouse gases are increasing in of CO2 absorb by Eco cement in comparison the environment this is the major problem with OPC and PPC. arising for world .this problem cannot be reduced but this can be minimized by eco Keywords: Brucite ⏐ durability ⏐ reactive friendly material eco cement. magnesium oxide ⏐ reactive magnesia ⏐ Eco-cements are hydraulic cements containing Portland cement ⏐ Portland pozzolana cement 15-20% reactive magnesia. When this reactive magnesia react with opc a brucite is form this Introduction is capable of absorbing co2 from environment. The most important characteristic of eco- Eco-Cement is made by heating magnesite in a kiln to produce reactive magnesium oxide cements is absorption of CO2 from atmosphere. Other properties affected include shrinkage, (magnesia). That magnesia powder is then added to a conventional Portland cement mix which, in turn, can be mixed with aggregates, For correspondence: in the usual fashion, to make Eco-Cement. 1Ujjain Engineering College Ujjain, M.P. Eco-Cement hydrates in permeable substrates, 2Medicaps Institute of Science and Technology, Indore using mix water, then carbonates. The more 3School of Engineering & Technology, Vikram University magnesia added and the more permeable it is, Ujjain, M.P. the more CO2 the Eco-Cement absorbs. An E-mail: [email protected] Eco-Cement concrete block typically takes up Comparative study of Eco Cement with OPC and PPC 30 Volume III Number 1 2012 [30 – 37] [ISSN 0975 - 6272] Vinay et al. to one year to carbonate fully, occurring A. Chemical Reaction of Eco Cement quickly at first and then slowing as the process MgCO3 MgO + ↓CO2 - Efficient low continues. Furthermore, should an Eco-Cement temperature calcinations structure reach its end-of-life or become obsolete, it can be almost fully recycled back MgO + H2O Mg (OH)2 – Hydration into cement. Mg (OH)2 + ↓CO2 + 2H2O → MgCO3 + 3H2O As we know that, incorporating pozzolans into – Carbonation cement mixtures is common practice, but In the cycle of chemical reaction of eco cement because Portland is alkaline there are strict it does not take much energy to go from one limits. Magnesium-based cements, however, state to another, it occurs at low temperature. are significantly less alkaline, leaving room for Magnesium Oxide which hydrates to much larger amounts of bulking material magnesium hydroxide and then carbonates is without compromising structural integrity. ideal for scrubbing CO2 out of the air and “We can probably get three of four times more sequestering the gas into the built environment. waste into our cement than Portland cement,” Methodology in Manufacturing the Eco Mr. Harrison has said buildings could become Cement massive ‘carbon stores’. 1. Magnesite (a compound of magnesium) is How do Eco-Cements work? obtained from quires and then it heated in a Eco -Cement is made by blending a small kiln to around 600 to 750 degrees C. The amount of reactive magnesia with conventional lower firing temperature of the Tec-Kiln hydraulic cements like Portland cement. As the makes it easier to use free energy such as magnesia hydrates it consumes water forming wind or solar or even waste energy and Tec brucite hydrates which can later deliver more Eco plan to make a kiln that does not use water for the more complete hydration of other fossil fuels and in which the CO2 gases hydraulic cement components adding to long produced from the magnesium carbonate as term strength development. We maintain that it decomposes is captured and contained lime should not be allowed to remain in for further use or safe disposal. concrete as it is far too mobile and reactive. 2. Eco cement also wants to grind in the hot Put some in your next cup of tea if you do not area of his kiln for increased efficiency. believe this! In Tec-Cement concretes lime produced as a result of the hydration of 3. The heating process produces reactive Portland cement is consumed by what is magnesia. known as the pozzolanic reaction with silica 4. The reactive magnesia (powder) is added and alumina and replaced by brucite which is in ordinary Portland cement. magnesium hydroxide and a much more stable 5. The resulting blended powder is eco and less soluble alkali. The result is that Cement. durability is significantly improved. Many other properties of concrete are favorably For experimental work of this paper the affected including the flow characteristics readymade the reactive magnesia (MgO (rheology) and dimensional change. Comparative study of Eco Cement with OPC and PPC 31 Volume III Number 1 2012 [30 – 37] [ISSN 0975 - 6272] Vinay et al. powder) available in market is added in OPC B. Standard Consistency Test about 15%. This is the test conducted to estimate the Comparison of Physical Properties quantity of water to be mixed in cement to For the comparison of physical properties of form a paste of normal consistency for use in Eco cement, about 15% MgO powder is other tests. The conventional method of Vicat properly mixed with the OPC. For this apparatus is used. Three trials are taken for all preparation the MgO powder is produced from three samples of cements, for different the chemical shop. Other two samples OPC 53 percentage of water. The standard consistency grade and PPC were used. All general physical found for all samples is under- properties of Eco cement are checked and compared with the ordinary Portland cement Type of standard S. No. and Portland pozzolana cement as under. Cement consistency A. Fineness Test 01 OPC 41 % The Sieve test is preferred for this purpose. 02 PPC 38 % Weigh correctly 100 grams of all three samples, took it on IS sieve No. 09 (90 03 Eco Cement 40 % microns). Break down the air set lumps in the samples with the fingers. Continuously sieving Table II: Standard consistency has been done in circular and vertical motion The above observations shows the standard for the period of 15 minutes. The residue left consistency of OPC, PPC and Eco cement was on the sieve was weighed. Three samples of found nearly same from different trials. each cement that is PPC, OPC and Eco cement C. Soundness Test was checked, the average results are as under- It is very important that the cement after setting shall not undergo any appreciable change of volume. This will cause serious Type of Average S. No. difficulties for durability of structures when Cement residue left unsound cement is used. The testing of soundness of the cement, to ensure that the 01 OPC 4.5 % cement does not show any appreciable 02 PPC 3.5 % subsequent expansion is of prime importance. The unsoundness of the cement is due to 03 Eco Cement 2 % excess of lime and magnesia or excessive proportion of the sulphates. As Eco cement Table I: Results of fineness test on cement samples contains percentage of magnesia more than As per standers the residue should not be more OPC and PPC there may be fear of than 10%. But it is observed that Eco cement is unsoundness, so this test become very essential finer than PPC and OPC. while comparing the Eco cement with other types of cements. The soundness of all there Comparative study of Eco Cement with OPC and PPC 32 Volume III Number 1 2012 [30 – 37] [ISSN 0975 - 6272] Vinay et al. samples of cements are tested by using the Le- time cement paste, mortar, or concrete should Chatelier apparatus. There samples of each be in plastic condition. The time interval for cement sample is boiled with the Le-Chatelier which the cement product remains in plastic mould. The differences between the initial and condition is known as the initial setting time. final distance of indicator points were noted. Normally a minimum of 30 minutes is given The average results are as under – for mixing and handling operations. Once the concrete is placed in the final position, compacted and finished, it should lose its Average differences plasticity in the earliest possible time so that it Type of between the initial is least vulnerable to damage from external S. No. Cement and final distance of destructive agencies. This time should not be indicator points more than 10 hours, which often referred as final setting time. 01 OPC 2.33 mm Initial Setting Time Test: For this test 02 PPC 1.67 mm conventional Vicat Apparatus is used with as usual procedure – Eco 03 3.00 mm Cement Type of Initial Setting S. No. Table III: Soundness of cement samples Cement Time Here from the observation the eco cement is looking somewhat unsound in comparison with 01 OPC 115 Minutes OPC and PPC. But as per the standard the 02 PPC 190 Minutes average differences between the initial and final distance of indicator points of Le- 03 Eco Cement 135 Minutes Chatelier mould must not exceed 10 mm, so though the expansion of Eco cement is slightly Table IV: Initial setting time more but it is well within the limit, so Eco cement can’t stated as unsound.