Refractory Mortars are finely grounded refractory mixtures used usually after the addition of water/binder to bind refractory bricks and to fill Refractory linings and seams. Refractory mortars consist of filler or aggregates, plasticizer and binder. Their composition usually must be compatible with the properties of the refractory bricks. A distinction is made among ordinary refractory mortars, which harden at high temperatures as a result of the formation of a ceramic bond; hydraulically hardening mortars, which contain hydraulic cement; and mortars with chemical bonding, which harden at room temperature or upon heating. Mixtures to which a non-ceramic binder has been added are called refractory cements [1].
Mortars consist of finely ground refractory materials which are then mixed with water to form a paste. They are used for laying and bonding shaped refractory products such as bricks. They are normally applied by trowelling [2]. The term Mortar is used to indicate a paste prepared by adding required quantity of water to a mixture of binding material like cement or lime and fine aggregates like sand. The above two components of mortar, namely, the binding material and fine aggregate are sometimes referred to as the matrix and adulterant respectively. The matrix binds the particles of the adulterant and as such, the durability, quality and strength of mortar will mainly depend on the quality and quantity of the matrix. The combined effect of the two components of mortar is that the mass is able to bind the bricks or stones firmly [1-2].
The degree of fineness of a refractory mortar is determined by its purpose. The grain size of fine-grained mortars does not exceed 1 mm (for some special mortars, 0.5 and even 0.1–0.2 mm); that ...
... middle of paper ...
...nerally their major constituent is also fine aggregate. Confusion sometimes exists over the difference between the terms fine aggregate and sand, there is in fact no difference the two words may be interchanged. Fine aggregate quality is affected by a number of factors: The mean particle size, grading, presence of impurities, shape, texture of the paricles. The selection of suitable aggregates, which are capable of producing a product with the optimum properties, is most important. The design of mortar mixes is based on the concept that the voids in the fine aggregate, which are generally in the range 25- 40%, will be filled with binder. Where the voids are not completely filled there is an increasing risk that the mortar will not be durable. Aggregate may be natural, manufactured or recycled [EDUCATIONAL GUIDE TOAGGREGATES, Experts in Mortar, Cemex Mortar][3][4].
14 What does reciprocally laying the mortars in a section do? it puts every mortar on the same azimuth of fire
Besides the known inventions and renovations of the Roman Empire, one of the building materials that the Roman Empire produced was concrete. With its strength, inexpensiveness and its easiness to work, the Roman Empire left an everlasting impact. Concrete that is a mixture of aggregate, which is usually gravel, sand or small stones, binding agents, and water is used to construct buildings and infrastructure. The first one, aggregate, gives the product its mass while the second one, binding agents, is used to harden the product. In the early times of the history, limestone powder was usually used as a binding agent in the mixture. The Romans later used “pulvis puteolanus” (pozzolanic ash), which was a fine volcanic ash as a binding agent and it allowed Romans to have strong concrete that is also durable (Yegeul, n.d.). It was easy to use
Once the brick has been identified, appropriate techniques can be determined for the repair of any defects within conservation guidelines. This report goes on to explore the properties of brick, repair and conservation methods available and finally the philosophical issues surrounding repair and cons...
Minerals are found worldwide and have many uses. The mineral gypsum is just one of the thousands named. Gypsum has always been a critical mineral in the building of many ancient constructions, and is being used still in today’s construction. (The History of Gypsum, 1985) It is speculated that the first use of it was in ancient Greece, where is was called “gypsos”, or “selenite”, but, gypsum’s first recorded use was in Ancient Egypt, where they used it in the building of the Pyramids. They used the material called “Alabaster” (which is a form of gypsum), but later in the 18th century, they realized that gypsum in its natural and raw state, was much too wet, so they altered it to create the building material called “Plaster of Paris”. (The Gypsum Association, n.d.)
This report takes the reader of the creation of SMA in Germany to its implementation in numerous other countries. The author organised a trip to Germany to see first hand how they combine the individual components to form the finish product. It was discovered that SMA was deformation resistant due to its solid aggregate skeleton structure. This a positive effect caused by the voids within the stone matrix being filled with a mastic of bitumen. The report looks at the use of SMA from the contractor’s point of view
If you want your homes to be strong and durable then nothing can work better than the masonry services. In fact, the durability of stone and bricks are immense and so choosing these products is indeed very essential if you want to avail a strong and sturdy abode. The experts offering you the services are experienced in their jobs and can thus offer the best homes in a jiffy. Simply browse online in order to choose these companies that will offer you the most comprehensive tile and brick homes on the go.
In this paper we have studied compressive strength of concrete by replacing natural aggregate with recycled aggregate by 25%, 50% and 75%.This mixture formed in the sample of cubes of dimension 150x150x150mm3.
Nanocrystalline perovskite and spinel magnetic mixed oxides materials have gained immense importance due to their novel properties, which are significantly different from those of their bulk counterparts [1]. Nanocrystals of spinel ferrites, with general formula MFe2O4 (where M = Ni, Cu and Zn) are most interesting class of magnetic materials due to its facinating properties such as low melting point, high spectfic heat, large expansion coefficent and low magnetic transition temperature[2,3]. Because of these properties, ferrite materials are widely used in ferrofluid technology, information storage and magnetic pigments[4-6]. Especially, due to their peculiar magnetic properties and ability to respond at the molecular level, magnetic nanostructures are potential candidates for biomedicine such as targeted drug delivery [7], diagnostics [8], and magnetic separation [9]. These materials are also being explored as contrast agents in magnetic resonance image (MRI) [10], thermo responsive drug carriers [11] as well as in the thermal activation therapy of cancer [12]. The crystal structure of spinel ferrite compounds have a cubic close packing of O2- ions structure linked with two sub-lattice sites namely tetrahedral (A-sites) and octahedral (B-sites) [13]. The magnetic and other properties of spinel ferrite can be varied systematically by changing the identity of the ion, their charges and their distribution among the tetrahedral and octahedral sites [14]. Zinc ferrite (ZnFe2O4) and cobalt ferrite (CoFe2O4) have been most extensively studied system, because they exhibit the typically normal and inverse spinel ferrite respectively [15]. Nickel ferrite (NiFe2O4) is a well known inverse spinel structure ferrite with Ni2+ ions at octahed...
Lime mortar the earliest form of concrete was invented by the Egyptian way before the time of the Roman republic. A mixture of lime derived from limestones, sand, and water gave a unique property to the material we know as concrete. The Romans apparently understood the number of advantages this unique mixture of building material offered which they called “opus caementicium” after one of the particular ingredients, caementa stone. The Roman style concrete was thicker than the concrete used today, therefore, working with it required a different technic.
High-shear colloidal mixers are internationally recognized as the most efficient method of mixing cement-based grouts and other materials. Colloidal mixing results in very stable mixes which resist bleed and water contamination.
Larger Hollow bricks (140 mm w x 90 mm h x 290 mm l) are generally used in cyclonic area to ensure reinforcement and grouting in the wall. Wider (150 mm wide) bricks are used in walls requiring lower sound transmission, greater fire resistance levels & higher load bearing capacity depending on the specific brick properties. Circular Cavities are made in bricks. Its’ benefits are that they aid in firing process, reduce weight for handling, provide better bond for mortar.
For the first assignment, I read two excerpts from Ceramics Art and Perception and one article from Ceramics Technical, the July 2017 edition. While each article focused on a different aspect of ceramics.
Concrete is a composite material used widely in the construction industry. Concrete is basically a mixture of cement, water, aggregates and admixture (sometimes). Cement is a fine gray powder that consists of oxidizes calcium, silicon and aluminum. The aggregate used is normally gravel, crushed stone or sand. Admixture is a solid or liquid substance that gives a certain characteristics of the concrete. The cement reacts with water chemically and binds the aggregates together through a process called hydration during hardening or curing of concrete. It means that water helps in the hardening of the concrete while the cement bind the aggregate and also react with water to form a solid mass.
Clay soils are usually referred to as very cohesive, as they retain a measurable shear resistance (a materials ability to resist forces that can cause the internal structure of a material to slide against itself), in the absence of confining forces. The ability of a cohesion-less or frictional soil such as sand or silt to support a building depends on the friction between its particles. Sand confined by surrounding soil within the earth can support a heavy building, whereas a conical pile of sand on the surface of the earth can support nothing, because there is little or no shear resistance between the particles.
The brick making process starts with the preparation of the clay with which the bricks will be made. This clay is then molded into the specified dimensions. There are two types of molding-Slop Molding & Sand Molding. Once dried, these molded bricks are transferred to a fire kiln where the bricks are subjected to a very high temperature to harden them. Now-a-days new manufacturing methods are replacing the conventional ones and some are still in practice. It’s because the conventional methods have some advantages as well as some disadvantages in some or other step. Based upon their disadvantages and advantages either they are being replaced by new methods or are still in practice. The advantages and disadvantages of these steps could be as follows:-