High Performance Concrete Materials and Their Use in Innovative Structural Solutions - Essay Example

Development and behavior of high performance concrete materials and their use in innovative structural solutions: submission: Abstract: In the recent times, an emerging technology referred to as HPC (high performance concrete) or UHPC (Ultra high performance concrete) has become quite popular in the construction industry. The component material of this substance depends on desired traits, as well as, availability of the appropriate local economic alternatives. The ultra high performance concretes have been utilizes in innovative structural solution, owing to their behaviors such as flexibility and unique combination. Introduction: Amongst the new types of concrete developed in the past twenty years, the high performance concrete has an extremely elevated compressive strength, as well as, durability with perfect flexural ductibility and resistance. And, with an ever-growing population, in addition to, expanding urban center, come increased level of constructions can be expected in all developing and developed countries. (Shuaib and Barker, 1991). Owing to enhanced mechanical property and durability, the high performance concretes have gained a wide acceptance in construction of innovative structures such as bridges, building and marine structures. Aitcin (2003), defines high performance concrete as the low water- binder concrete with optimized aggregate to binder ratio of controlling its dimensional stability (for examples, drying shrinkage) which receives the sufficient water necessary for controlling autogenous shrinkage. Though high performance concrete has extensive application, its production is limited in various nations owing to the fact that suitable concrete aggregate like river sand, hard crushed or gravel aggregates are not available or either is available only in restricted quantity. Background research in HPC: An all-embracing research has been carried out for the purposes of developing blended cement, concrete, as well as, other construction materials (self consolidating concrete, high performance, fibre reinforced concrete or lightweight concrete) for sustainable development with industrial and natural waste like fly ash, cement kiln dust, volcanic, as well as, slag materials. The developed blended cements and concrete materials did make a wonderful impact in the cement manufacturing and construction industries in many countries. At the moment, they are being utilizes in the common construction and in the restoration projects. The United States department of Transportation shows that the high performance concrete have a tendency of having compressive strength of over 150MPa, interior fibre reinforcement of ensuring brittle behavior, as well as, a higher bidder content with the special aggregates. Moreover, high performance concrete have a tendency of having lower water content, in addition to, being capable of achieving adequate rheological properties via a combination of some optimized granular stuffing and an addition of higher range water decreasing admixtures. An example of high performance concrete available in America is Ductal® that have the properties shown in appendix 1. Appendix two shows the shows a range of material characteristic for the Ultra high performance concrete. Appendix 1 properties of a high performance concretes Appendix 2 Advantages of a high concrete material Owing to the environmental impacts that are associated with the aggregate extraction, some substantial efforts have been made towards utilization of waste and indigenous materials (by-product) in concrete. The key advantages of utilization of by-products from a number of origins in production of HPC are the exclusion of scraps, as well as, reduction in overexploitation of quarries. Consequently, the application of these by-products has been recommended as aggregate for some high performance concrete: vitrified flooring, construction rubber, plastic, glass, remnants of asphalt agglomerates, in addition to, steel making slag or metallurgical. The byproducts have been tested with some varying extent of success. Discussion: The advances in science of concrete substances have already resulted to development of newer classes of some cementitious composites referred to as high performance concrete (HPC). HPC is basically a cementitious composite made of optimized gradation of constituents of granular, water to cement material ratios of lesser than ¼ and the high percent of sporadic internal reinforcement of fiber. Mechanical properties of an ultra high performance concrete comprise of compressive strength bigger than 21.7 ksi (150 MPa), in addition to, sustained post cracking tensile strength bigger than 0.72 ksi (5 MPa).  Ultra high performance concretes has discontinuous pore structure which decreases liquid ingress, considerably enhancing durability in comparison to the conventional concretes. The mechanical, as well as durability properties of high perforce concrete makes it the ideal candidate for application in developing new and innovative solution to the pressing on highway infrastructure corrosion, replacement and repair. From the year 2000, when HPC became available commercially in the US, a series of project research has shown the capabilities of this material. A variety of departments (transportation) have deployed components of high performance concretes in their infrastructures, whilst many more organization is actively considering application of the HPC. The high performance concrete is considered for the utilization of a wide variety of road infrastructure applications. The behavior of being strong tensile wise and highly compressive allows it to be used in optimization and redesign of structural elements. At the same time, its improved property of durability facilitates lengthening of the design life, in addition to, allowing for some prospective use as claddings, thin overlay and shells. As far as the United States is concerned, HPC has been utilized in the prestressed concrete support simple span bridges, field cat’s connection between the fabricated bridge components and pre-cast concrete deck panels. Appendix 3 shows the HPC highway bridge made in the United States. Appendix 3: HPC have shown exceptional perfomace in its utilization as grout material or field cast closurein pplications which needs the onsite connection from multiple prefabricated components. The utilization of HPC has acquired a significant momemnt of late, with most states considering its application. Appendix 4 below, shows HPC being field cast in a deck leveled connection between 2 deck bulb tee pre-stressed girders, Appendix 4 Also, HPC is being investigated for the use in a variety of much other application. They comprise of precast concrete pile, thin bonded covers on deteriorated bridges, seismic retrofit of some substandard bridge structures, security, as well as, in blast mitigation applications. Generally, HPC has demonstrated that it is particularly pertinent in its applications to innovative structural solution where the traditional methods have been lacking (Bernardo and Lopes, 2004). Connection solution for instance, has hindered the application of some prefabricated components, whilst HPC allows for simplification and redesign of a system whilst at the same time promoting a long-term durability. Conclusion: High performance concrete has some unique behaviors as shown in its development and application in various innovative structural solutions. The material’s exceptional combination of design flexibility and superior properties facilitates architects’ capability of creating attractive and strong structures. In essence, this material provides solution with the advantages like speed of construction, superior durability, improved aesthetics, as well as impermeability against corrosion, impact and abrasion that translates to longer life span and decreased maintenance. All this proves the extent to which every construction sector should consider use of HPCs. Bibliography: Aitcin, P. C. (2003). “The durability characteristics of high performance concrete: a review,” Cement and Concrete Composites, vol. 25, no. 4-5, pp. 409–420, Shuaib A. and Barker, R. (1991). “Flexural behavior of reinforced high-strength lightweight concrete beams,” ACI Structural Journal, vol. 88, no. 1, pp. 69–77, Bernardo L. F. and Lopes, S. M. “Neutral axis depth versus flexural ductility in high-strength concrete beams,” Journal of Structural Engineering, vol. 130, no. 3, pp. 452–459, 2004. Read More