The Pros And Cons Of Reinforced Concrete

Proc., 7th Int. Conf. on Fracture Mechanics of Concrete and Concrete Structures. Korea Concrete Institute,

On comparing to a reinforced concrete component, an element made of high strength concrete will have minor deflection, slighter camber change, lower pre-stress loss and longer life relatively. Additionally, it gives heightened shear capacity of columns and stronger beam-column joints. The other characteristics of high strength concrete are higher compressive strength, better tensile strength and improved

The aim of this experiment was to test the workability and compressive strength of three different batches of concrete, each containing different water to cement (W/C) ratios.

According to Tam (2002) concrete is a commonly used construction material in most parts of the world.There are many different types, strengths, and compositions of concrete and all of them have different characteristics that make them perform better for different applications. The following report is an outline of the different aspects of concrete itself. It includes the special concretes and their applications that are best suited for the construction of a shopping mall, the types of extenders that may be used together with the different admixtures.

Concrete is a significant structural material used all around the world. Moreover, the complexity of structures and their magnitude have continued to increase, and this has resulted in a greater importance of their strength and distortion characteristics in more serious consequences of their behaviour. Engineers have been working on the development of innovative types of concrete. One of the most promising products is fiber-reinforced concrete (FRC). Fibers in concrete provide better-quality mechanical and physical properties of the material. For example, the obtained fiber-reinforced concrete has higher resistance to cracking. In this paper we will be discussing fiber reinforced concrete as an alternative to the conventional concrete.

This research work focus on Compressive strength, flexural strength and Bond strength of Conventional Concrete (CC) and Class C fly ash blended concrete incorporation with Natural Admixture. Broiler hen egg was used as Natural admixture (NAD) to study the effect of NAD on strength properties. The Class C fly ash was replaced to cement at various levels and NAD was replaced to liquid and identified the optimum replacement level of Class C fly ash and optimum dosage of NAD by maintaining the constant liquid contant 0.55 to achived M20 grade concrete. The compressive strength, flexural strength and bond strength of concrete for both CC and FA concrete. The studies reval that the optimum replacement of Class C fly ash is 25% and optimum dosage of NAD is 0.25% based on strength results.

The tensile force transferred from the steel bar through the bond to the concrete is illustrated and compared for difference reinforcement ratio (ρ = 0. 5%, 0.89% and 1.12% for steel 12 mm, 16 mm and 18 mm) in figure (5.79) and table (5.17). Before first crack accured (Pre-cracking stage), the precentage of tensile force transferred from the steel bar to the concrete accounts is about 8%, 13% and 16%. Aftere first crack accured (cracking stage), the precentage of tensile force transferred from the steel bar to the concrete is about 53%, 60% and 72%. During Post-cracking stage almost all the tensile force is carried by the steel bar 82%, 89% and 90% for P-12- FEM, P-16-FEM and P-18-FEM respectivily.

Now a day, civil engineering structures require high strength and high durability concrete for construction, but at the same time concrete should be economical. This requirement leads to the development of concept of Self Compacting Concrete [1]. As Self Compacting Concrete completely fills the formwork by virtue of its own weight without segregation so dense matrix is formed which increase the strength and durability of structure [2]. But Conventional Self Compacting Concrete has low tensile strength, little cracking resistance and limited ductility. This limitation can be eliminated by addition of fibers [3]. Fibers have the potential to increase the post cracking energy absorption and enhancing the ductile character of concrete structure [4,5]. Also when, Steel Fiber Reinforced Self

Over the past quarter century, the number of both experimental and analytical studies have increased dramatically on the monotonic axial behavior of FRP-confined concrete columns, and as a result, many uniaxial stress-strain models have been generally developed; however, most of these studies have focused largely on FRP-confined circular plain (unreinforced) concrete cylinders numerous authors tested (e.g., Mirmiran and Shahawy 1997;Mirmiran et al.1998; Xiao and Wu 2000; Lam and Teng 2002,2003;Berthet et al.2005;Almusallam 2007; Benzaid et al.2008;Eid and Paultre 2007,2008;Teng et al. 2009;Smith et al. 2010;Cui et al.2010). Relatively few of which have included small or medium scale noncircular unreinforced specimens

Self-compacting concrete (SCC) is a flowing concrete mixture that is able to consolidate under its own weight. The highly fluid nature of SCC makes it suitable for placing in difficult condition & in selections with congested reinforcement. Use of SCC can help in hearing related damages on the worksite that are induced by vibration of concrete, another advantages of SCC is that the time required to place large section in consider ability reduced. When the construction company in Japan experienced a decline in the availability of skill labour in the 1930's a need for felt for a concrete that could overcome the problem of defective workmanship.

The macroscopic material behavior of concrete is influenced by the geometry, spatial distribution and material properties of individual material constituents and their mutual interactions. Therefore, it is essential to study the influence of each material constituent in order to estimate the residual strength of the structural components. Thus, failure of concrete is a complex phenomenon due to its multiscale and multiphase nature. When the normal stress in a material reaches its tensile strength, the inhomogeneities in concrete promote the formation of an inelastic zone ahead of an existing crack termed as the fracture process zone (FPZ). The FPZ is dominated by various complicated mechanisms such as crack shielding, crack deflection, aggregate bridging and microcracking around the crack tip and exhibits a post-peak softening behavior under tensile loading. It therefore becomes necessary to include these effects for predicting reasonably well the residual strength of existing cracked and damaged structures.

Infrastructure development across the world created demand for construction materials. Concrete is the most important construction material. Concrete is a mixture of various ingredients like aggregates, water and admixture. Aggregate form is the major part of concrete among the entire ingredients used in concrete. The use of normal weight of aggregate such as gravel and granite probably reduces the natural stone deposits and it cause effect on environment. Therefore, it is necessary to explore and to find out suitable material for the replacement and to substitute the natural stone. In foreign countries, the natural and artificial light weight aggregate has been identified

Concrete as is well known is a heterogeneous mix of cement, water and aggregates. The admixtures may be added in concrete in order to enhance some of the properties desired specially. In its simplest form, concrete is a mixture of paste and aggregates. Various materials are added such as fly ash, rice husk, and admixture to obtain concrete of desired property. The character of the concrete is determined by quality of the paste. The key to achieving a strong, durable concrete rests in the careful proportioning, mixing and compacting of the ingredients.

Cement production is the result of chemically combination of different materials. These materials include “calcium”, “silicon”, “aluminum”, “iron” and other materials such as clay and limestone. Moreover, the production process involves crushing and screening of certain amount of “calcium compounds”, “silica”, “alumina” and “iron oxide”. After this process the whole mixture is placed in “rotating cement kiln”. Different kind of materials are used in this regard. These include “limestone”, “sandstone”, “marl”, “shale”, “iron”, “clay”, and “fly ash”.

Abstract-Concrete is the most widely used construction material in civil engineering industry because of its high structural strength and stability. Cement and sand is a major constituent material of the concrete which produced by natural raw material like lime and silica and natural sand respectively. Once situation may occurs there will be no lime on earth production of cement also natural sand. This situation leads to think all people working in construction industry to do research work on cement replacing material and natural sand for use of it. The construction industry is constantly looking for supplementary cement and natural sand material with the objective of reducing the solid waste disposal problem. Ground granulated blast furnace slag (GGBS), quarry sand are the solid wastes generated by Industry. To overcome from this crisis, partial replacement of Cement with GGBS, natural sand with quarry sand (QS) can be an economic Alternative. The cubes are tested for compressive strengths. Ordinary Portland cement was partially replaced by GGBS of 0%, 30%, 40%,50% and natural