Advanced Materials for Construction - Coursework Example

Advanced materials for construction Name Institution Subject Instructor Date Abstract There has been great change in the construction materials as Engineers seek materials that exhibit a number of properties such as readily available, affordable and that are friendly to the environment. The properties that are enhanced include; strength and the rigidity of the material. This has seen a paradigm in the modern engineering application, where advanced materials have been used in the construction industry. This has seen materials such as the reinforced polymer composites in use. This paper discusses the advanced fibre reinforced polymer composites and their advantages over the conventional construction materials, the shortcomings. The future construction materials are also discussed in the paper. Key words; Composites, polymer, Fibre, reinforced, Resins 1 .Introduction In the recent past, the construction industry has witnessed immense utilization of advanced polymer composites. These changes have positive contributed to the contributed to changes in the manufacturing techniques. Apparently advanced polymer composites (APCs) have many advantages over the conventional engineering materials as stipulated by Hollaway (2007). Consequently, the mechanical properties of APCs are such that, if when combined with the reinforced concrete such as; steel and timber, they tend to form impeccable construction materials. They form structures that are resistant to various environmental conditions as well as offering impressive appearance. Firstly, a composite is made up of reinforced structure that constitutes a continuous matrix that would surround a given structure. The reinforcement offers great amount of strength and stiffness while the matrix ensures that the fibres are strongly bonded. This is achieved by using fibres that have high strength so as to ensure that the mechanical stress are properly conducted 2. Literature review 2.1 Reinforcement of APCs The continuous matrix forms the basis of APC matrix that exists in the fibre reinforcement that exists between the two layers. This ensures that the desired properties are attained as noted by Cadei, Stratford, Hollaway & Duckett (2004). 2.2 The polymer This consists of a series of monomers that forma large organic compound namely the polymer. As noted by Tinazzi, Modena & Nanni (2000). The function of the polymer includes: They aid in binding the fibres together to inhibit cases of abrasion and corrosion surfaces. Hold fibres strongly and transferring the adhesive forces that enhance the shear strength of the matrix. Providing surface finish to the structural members. Ensuring the required chemical and thermal compatibility is maintained. There are various types of polymers that exist. They include; Epoxies, Thermoplastic, Elastomers and the Thermosetting. 2.3 Thermoplastics polymers These are polymers made of long chain molecules bonded by weak Vander Walls forces. There valence bonds are strongly bonded and exhibit hg strength. This makes them to have high molecular weight (Hollaway & Head, 2001). Polyolefin and the polyesters form the main polymers that are used in construction purposes. Additionally, the geosynthetics are mainly used in construction purposes. 2.4 Thermosetting polymers These are types of polymers that when they are exposed to heat, they cannot be reversed. They undergo a process known as polycondesation. The presence of the cross linking ensures that the stronger network is produced depending on its density and length. The network length would in turn depend on the chemical components while the cross linking would depend on the nature in which curing was done, and the prevailing temperature when polymerization was taking place. The main examples of the thermosetting that find their application in construction include; Epoxies, vinylesters and the phenolics 2.5 Elastomers These types of polymers are usually used in form of either reinforced or un-reinforced rubber as they exist in long chains (Hollaway, 2007). Their molecules are randomly coiled that enables them to exhibit high amount of molecular flexibility. They are capable of undergoing any amount of defamation. They find their application in the construction of elastomeric bridge bearings and in making the resilient seats. 2.6 The Epoxies The low weight oligomers are the main epoxies that are used for construction purposes. They emanate from the reactions that exist between the biphenyl A and epichlorohydrin. Their advantages include; They posses high specific strengths and dimensional stability Are resistant to high temperatures and solvents like alkali Posses high toughness 3 Engineering properties These include the mechanical properties of various materials. These include the specific strength , modulus of elastic as well as the coefficient of linear expansion of various thermosetting materials. These are as illustrated in table2 below in the appendices. 3.1The Fibres There are a number of fibres that are used in the structural work. These may include, glass, aramid fibres as well as the carbons. Additionally, the synthetic fibres are composed of polyethylene and the polypropylene. On the other hand, the glass fibres are composed of silica compounds that consist of the oxides of metals that form these glasses. Glass has high strength that enhances the strength of the structural The most important grades as noted by Cadei, Stratford, Hollaway & Duckett (2004) are: E-glass –it contains minimal alkali content at ranges of 2%. It is being used for general purpose structural works. It also has great heat and electrical resistance. R-glass – Exhibit has high tensile strength ad able to withstand high temperatures. S-glass- Has high stiffness and high resistance to electricity for heat and corrosion 3.1.1Carbon fibre Include the high and low modulus fibres. They are applied in scenarios where the structures require high modulus of strength. Curing the products at high temperatures increases the performance of the APCs. This is achieved by regulating the temperatures that are utilized. This ensures that the fibres are not degraded further and they maintain the high level of compatibility. Moreover, the inclusion of the nano particles enables the polymers to exhibit high resistance to fire as well as increasing its mechanical properties. 3.1.2 Adhesives They have been used in the recently as sealants that are used in a number materials. They have been used in bonding the concrete and metallic surfaces. Its application is being used to bond between hardened concrete other construction materials such as steel and APCs. Similarly, the nature of repairs on our roads has changed since we can’t afford to close lanes with the increased traffic. The polymeric materials and other sealants are used for refurbishing metallic and concrete structures. It has been proved that the strength of an adhesive is dependent on the adhesive strength between the substrate and their adhesive strength of the material. 4 Current structures built using advanced construction materials An example of an all composite structure is the Lancashire GFRP classroom of UK. The building uses fibre made of polyester resin as the building blocks. Moreover, the bonds mills bridge in 1996, is another example of a structure constructed using the advanced construction materials that utilizes ten identical pultruded ACCS (Advanced Composite Construction System). They also incorporate the E fibre glasses that are made of maunsell planks. Figure 1 The GFP classroom (Domone & Illston, 2010) Figure 2 The GFRP Bridge, UK (Domone & Illston, 2010) 4.1 Miscellaneous Evidently, it is clear that, that the APCs material remains a unique system designed to give an edge over the conventional materials. It therefore requires innovativeness by Engineers so as to exploit the full advantages (Hollaway, 2007). This is because, the exhibit high durabity as well as form complex structures such as the transmission towers. 5 Future construction materials The development of new technology fosters the application of materials that would be readily available and are affordable. Firstly, the application of the carbon nanotubes is increasingly on the use. They form bonds that are strong and exhibit high tensile strength as well as, high electrical conductivity. This makes them to be effective in space elevators applications. Moreover, the super alloys can find their application in the construction industry as they can operate at high temperatures. This makes to be in application of scramjets and the ramjets. Their ability to withstand, creep enables them to be used on making floating spaces as they have the capability of withstand high speeds. References Cadei, J M C., Stratford, T J. Hollaway, L C. and Duckett, W G. (2004). ‘Strengthening Metallic Structures Using Externally Bonded Fibre-reinforced Polymers’ Pub. CIRIA, London. Domone, P & Illston, J. (2010). Construction materials; Their nature and behaviour. UK; Wiley. Hansen, K. L., & Zenobia, K. E. (2011). Civil engineer's handbook of professional practice. Hoboken, NJ: Wiley Hollaway L C (2007). ‘Survey of Field Applications’ Chapter 12, ‘Durability of Composites Civil Structural Applications’,Edited by V. M. Karbhari published by Woodhead Publishing, Oxford. Hollaway, L. C. & Head, P R (2001), ‘Advanced PolymerComposites and Polymers in the Civil Infrastructure’. Pub.Elsevier, Oxford. Mouton, Y. (2010). Organic Materials in Civil Engineering. Iste/Hermes Science Pub. Tinazzi, D., Modena, C. & Nanni, A. (2000), ‘Strengthening of Masonry Assemblages with Fiber Reinforced Polymer Rods and Laminates’, Proceedings: Advancing with Composites 2000, Milan, Italy. Somayaji, S. (2001). Civil engineering materials: [...]. Upper Saddle River, NJ [u.a.: Prentice Hall. . Appendices Table 1 Types of carbon fibre (Tinazzi, Modena, & Nanni, 2000) Table 2 The mechanical properties of the polymers (Tinazzi, D., Modena, & Nanni, 2000) Read More