EXPERIMENTAL STUDY OF MAGNESIA CEMENT

Transcription

1 EXPERIMENTAL STUDY OF MAGNESIA CEMENT J. Ramesh 1, N. Rajiv Gandhi 2, M.Rajkumar 3 and P.Veeraraghavan 4 1,2,3,4 Assistant Professor, Prince Shri Venkateshwara Padmavathy Engineering College Abstract This investigation focuses on emission of co2 coupled with non-absorption of the same on account of deforestation etc. has caused tremendous environmental pollution leading to global warming and other bad effects. It is estimated that about 7% of greenhouse gas is being emitted into the atmosphere annually on account of production of OPC alone. So it is a need of the time to find some substitute of cement. In order to reduce the environmental pollution.in this experimental investigation, we were replaced the cement by using magnesia for manufacturing of concrete along with coarse aggregate and fine aggregate. Magnesium deposits exist in abundance in every corner of the earth and cover roughly 8% of the world s surface. Depending upon where they are mined, magnesium oxide and magnesium oxide/magnesium chloride cements require only 20%-40% of the energy required to produce Portland cement. Magnesium oxide is extracted from magnesium ore like as magnesium carbonate, dolomite, and magnesium sulphate. As compared to burning of limestone it will produce less amount CO2.So replacing the calcium oxide by magnesium- oxide. The magnesium have lower atomic radius than the calcium. Hence it has higher strength and denser. We were prepared cement by mixing of magnesia and un-calcined clay. In the sources of materials, to hydrate to form M-S-H gel. The M-S-H gel binds the loose coarse and fine aggregates to form concrete. M-S-H gel replaces the C-S-H gel in OPC cement. For this purpose along with a Control Mix, 45 cubes are prepared to study the compressive strength. Test on magnesia based cement and coarse aggregate, fine aggregate are conducted as per Indian standards. Results shows the strength of magnesia based cement concrete. Index Terms Magnesia cement [Font: Times New Roman, Size:9]About four(minimum) key words or phrases in alphabetical order, separated by commas. I. INTRODUCTION A cement is a binder, a substance used in construction that sets and hardens and can bind other material together. The history of cementing material is as old as the history of engineering construction. Some kind of cementing materials were used by Egyptians, Romans and Indians in their ancient constructions. It is believed that the early Egyptians mostly used cementing materials, obtained by burning gypsum. The Greek and Romans later became aware of the fact that certain volcanic ash and tuff, when mixed with lime and sand yielded mortar possessing superior strength and better durability in fresh or salt water. Roman builders used volcanic tuff which is mostly siliceous in nature thus acquired the name Pozzolana. Later on, the name Pozzolana was to any other materials, natural or powdered artificial, having nearly the same composition as that of volcanic tuff or ash found at Pozzuli. The Romans, in the absence of natural volcanic ash, used powdered tiles or pottery as pozzolana. In India, powdered brick named surkhi had been used in mortar. The Indian practice of through mixing and long continued ramming of lime mortar with or without the addition of surkhi yielded strong and impervious mortar which confirmed the secret of superiority of Roman mortar. When we come to more recent times, the most important advance in the knowledge of the cement, the forerunner to the discoveries and manufacture of all modern cements is undoubtedly the investigations carried out by John Smeaton. He concluded that lime stone which contained considerable proportion of clayey matter yielded better lime possessing superior hydraulic properties. The investigations of L.J.Vicat led him to prepare an artificial hydraulic lime by calcining an intimate mixture of limestone and clay. II. MAGNESIA CEMENT This process may be regarded as the knowledge to the manufacture of Portland cement. Nowadays the demand of cement is increasing for all type of construction the cement is used. Usually manufacturing of cement involves burning of limestone which is a highly polluting the environment by emitting CO2. So the cement is prepared without using lime there by effects in the environment become less. In old period the MgO is used as a binder. And also the process of MgO based cement is simple and easy. IJIRT INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN TECHNOLOGY 158

2 In this process the magnesium oxide is extracted from the ore and mixed with uncalcined grained clay and then used as a binder. In the manufacturing process, it requires only less energy consumption and less amount of is CO2 produced compared with conventional cement In this experiment, three samples are prepared and studied the behavior. These are, MgO + china clay, 2. MgO + bentonite clay, 3.MgO + cow dung III. PREPARATION OF DESIGN The mix design is in the occurrence with Indian mix design method. A careful procedure is adopted in the batching, mixing and casting operation. The coarse aggregate and the fine aggregates were weighed first accurately. The concrete mixture is prepared by mixing machine on a water tight platform. Specimens were shifted to curing yard. A. Casting The cube mould plates should be removed, properly cleaned assembled and all the bolts should be fully tight. A thin layer of oil then shall be applied. After taking concrete samples and mixing them, the cube shall be cast as soon as possible. B. Curing The casted cubes shall be stored under shed at a place free from the vibration at a temperature 220c to 330c for 24 hours. After 24 hours the cubes are removed from mould and immersed in clean water till the 7 to 28 testing. IV. RAW MATERIALS A. Magnesia Cement In this MgO cement, a new manufacturing technique is going to be adopted. This manufacturing process emits only less CO2 is produced. o The conventional cement manufacturing process contains the following process. o In the MgO based cement manufacturing process contains the following process Raw materials (Mg ore only) (Exothermic) Here Mg ore is only calcined. The uncalcined clay is mixed with magnesia. In exothermic process, we added water to the raw materials and get the binding material. The products are M-S-H gel and Mg(OH)2. o Another cement is prepared by mixing of magnesia, water, and cow dung. This is the magnesium phosphate cement. This process is given by, MgO + H 2O 3Mg(OH) H 3PO 4 Unhydration process Mg(OH)2 Hydration process Mg3((PO)4)2 + 6H2O Cow dung has nitrogen, phosphorous, and potassium in the ratio of 3:2:1. Hence the cheaper phosphorous was used for preparation of MPCs. Raw material Hydration process ( limestone + clay) (Exothermic) In endothermic process, the raw materials are fully calcined (limestone + clay). In Exothermic process, water is added to the calcined materials and it absorbs water and gets hydrated. The products are C-S-H gel and Ca(OH)2. Fig.1: Process of Magnesia Cement B Coarse Aggregate Aggregate are the important constituents in concrete. They give the body of the concrete and also reduce the shrinkage. Earlier, aggregates were consider as IJIRT INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN TECHNOLOGY 159

3 chemically inert materials but now it has been recognized that some of the aggregates are chemically active and also that certain aggregates exhibit chemical bond at the interface of aggregates and paste. Test on aggregates were tested and classified by IS C. Fine Aggregate Fine aggregate or sand is an accumulation of grain of mineral matter derived from the disintegration of rocks.it is distinguished from gravel only by the size of the grains or particles, but is distinct from clays which contain organic matter. Sand that have been sorted out and separated from the organic materials by the action of current of water or by winds across arid lands are generally quite uniform in size. Usually commercial sand is obtained from river beds or sand dunes, originally formed by the action of wind. Fine aggregates are classified according the results from testing of fine aggregates. Test on fine aggregates were tested and classified by IS The test specimens are stored in place free from vibration, in moist air of at least 90% relative humidity and at temperature of 27 ± 2 C for 24 hours ± ½ hour from the time of addition of water to the dry ingredients. The magnesia cement concrete was kept in room temperature for air curing for 3 days. After 3 days, the specimens immersion in water. The specimens were kept under water for 7,14 and 28 days respectively. The water or solution in which the specimens are submerged, are renewed every seven days and are maintained at a temperature of 27 ± 2 C. After curing, the specimens were taken out from the curing tank and air dried before testing. VI. RESULTS AND DISCUSSION A. Test on Mortor Cube Strength Table.2: Compressive strength of mortor at 7 th day V. MANUFACTURING PROCESS A. Mix Design Table.1: Mix Proportion B. Casting The test cube specimens were made after mixing and in such a way as to produce full compaction of the concrete. The moulds were filled with concrete. Each layer is compacted by hand using the standard tamping rod and the strokes of the rod are distributed in a uniform manner over the cross-section of the mould of size 7.06 cm. The area of the face of the cube will be equal to 50 sq cm C.Curing Fig.2: Compressive strength of mortor at 7 th day IJIRT INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN TECHNOLOGY 160

4 Table.3: Compressive strength of mortor at 14 th day Fig.4: Compressive strength of mortor at 28 th day Fig.3: Compressive strength of mortor at 14 th day Table.4: Compressive strength of mortor at 28 th day Fig.5: Compressive Strength of Mortor Cube B. Test on Concrete Cube Strength Table.5: Compressive strength of Concrete at 7 th day IJIRT INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN TECHNOLOGY 161

5 Table.7: Compressive strength of Concrete at 28 th day Fig.6: Compressive strength of Concrete at 7 th day Table.6: Compressive strength of Concrete at 14 th day Fig.8: Compressive strength of Concrete at 28 th day Fig.9: Compressive Strength of Concrete Fig.7: Compressive strength of Concrete at 14 th day IJIRT INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN TECHNOLOGY 162

6 VII. CONCLUSSION By this investigation, the emission CO2 of is reduced and energy consumption while the manufacturing process is saved. The cement contains 4 to 6% of MgO. If exceed, it produce undue expansion during hydration. A compressive strength of mortar and concrete is decreased when the magnesium oxide is fully replaced. So we replace 10% of cement with MgO and it increases the compressive strength. The slump value is not much affected. It requires 3 days of air curing before the immersion of water. And also we believe that by adding some bonding admixtures themselves, the fully replacement gives better result. Incorporation of MgO improves the water tightness and strength of the cement (optimum amount 10%). Hence in powdered form, it is a good additive. For the further development of the magnesia cement markets, should be the undertaking of R&D efforts aiming at higher standardization of the magnesia cement technology. [ 10 ] IS 7320, Specification for Concrete Slump Test Apparatus, Bureau of Indian Standards, New Delhi (1974). [ 11 ] IS12269, Specifications for 53 Grade OPC, Bureau of Indian Standards, New Delhi (1987). [ 12 ] IS2386, Methods for Test for Aggregates for Concrete, Bureau of Indian Standards, New Delhi (1963). [ 13 ] IS10262, Concrete Mix Design, Bureau of Indian Standards, New Delhi (2009). REFERENCES [ 1 ] Chongjiang Du A review of magnesium oxide in concrete by 2005 [ 2 ] George Swanson Magnesium oxide, Magnesium chloride-based cements [ 3 ] Hollemen, A.F: Wiberg, E. Inorganic chemistry acadamy press, 2001 [ 4 ] M.Halaris, dr. Th.Zampetakis. Magnesia cements by [ 5 ] Kelly hart. Magnesium based cements by 2001 [ 6 ] K.J.Sam Paul Jeba Nim, S.Manjuladevi, dr.s.senthilkumar Rapid setting sorel cement with m-sand strength and workability aspects by [ 7 ] Ritu Mathur and Sanjay K. Sharma Magnesium oxysulphate cement: change in properties on admixing sodium bicarbonate as an additive by [ 8 ] R N Yadav, Upendra Singh, Priyanka Gupta, Madhu Sharma. The effect of mgcl2 solution density on the phases in magnesia cement paste [ 9 ] Zongjin Li, Zhu Ding, and Yusheng Zhang. Development of sustainable cementitious materials IJIRT INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN TECHNOLOGY 163