Abstract – Concrete occupies unique position among the modern construction materials, Concrete is a material used in building construction, consisting of a hard, chemically inert particulate substance, known as a aggregate (usually made for different types of sand and gravel), that is bond by cement and water.Self – compacting concrete (SCC) is a high – performance concrete that can flow under its own weight to completely fill the form work and self consolidates without any mechanical vibration. Such concrete an accelerate the placement, reduce the labor requirements needed for consolidation, finishing and eliminate environmental pollution. The so called first generation SCC is used mainly for repair application and for casting concrete in …show more content…
The proto type performed satisfactorily with regard to drying and hardening shrinkage, heat of hydration, denseness after hardening, and other properties. This concrete was named “High Performance Concrete” and was defined as follows at the three stages of concrete:
1. Fresh : Self – Compactable.
2. Early age : Avoidance of initial defects
3. After hardening: Protection against external factors.
“High Performance Concrete” was defined as a concrete with high durability due to a low water-cement ratio by professor Aitcin et al (Gangneetal 1989). Since then, the term high performance concrete has been used around world to refer to high durability concrete. Therefore, H.Okamura and M.Ouchi, the authors, of an invited paper on SCC for JACT 2003 have changed the term for the proposed concrete, for their work, to “Self – compacting High performance Concrete”.
1.4 MECHANICAL CHARACTERSTICS:
Characteristic compressive strength at 28 days shall be 25 – 60 Mpa.
Early age compressive strength shall be 5 – 20 Mpa at 12 – 15 hours (Equivalent age at200 C)
“Normal” creep and shrinkage
1.5
…show more content…
The job of SP is to impart a high degree of flow ability and deformability, however the high dosages generally associate with SCC can lead to a high degree of segregation. Conplast SP 430 is utilized in this project, which is a product of FOSROC Company having a specific gravity of 1.222. Super plasticizer is a chemical compound used to increase the workability without adding more water i.e. spreads the given water in the concrete throughout the concrete mix resulting to form a uniform mix. SP improves better surface expose of aggregates to the cement gel. Super plasticizer acts as a lubricant among the materials. Generally in order to increase the workability the water content is to be increased provided a corresponding quantity of cement is
The purpose of this short memo is to discuss aspects of use, applicability, and environmental impacts of porous pavements as gleaned from practical findings and pertinent examples. A porous pavement is one with high enough porosity and permeability to allow rain and snowmelt to pass through it, thereby reducing the runoff from a site and surrounding areas. In intensely built up areas, pavements account for more than half of all the land, and for about two-thirds of total built cover (Ferguson, 2005, 2-3). Parking lots, in particular, account for the majority of paved areas. Pervious paving materials have the capability of providing a dual purpose in parking and other areas with low to moderate traffic; they serve both as a parking/traffic area and to manage stormwater.
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
Lastly, Figure 2 and Figure 3 represent a collection of data obtained from the students in class. To determine a correlation between two variables we used the “coefficient of determination” which is also known as r-squared. Based on Figure 2, the r-squared value was 0.292. This r-squared value indicated that there appears to be no relationship between the muscle size and maximum muscle force. In comparison, in Figure 3 the r-squared value was 0.038. Thus, this r-squared value also indicated that there is no relationship between the muscle size and half-maximum fatigue
Thus, to enable strength to body mass ratio to be calculated. Additionally, it was mentioned balance and problem solving skills of the individual could play an important role (Giles et al., 2006).Suggesting problem solving skills should also be assessed. Furthermore, it would be advisable to assess the individual’s ability to climb rock walls with varying grades in difficulties.
Compressions: Start 100X 1 min chest compression lots of 30 and 2 breaths then check pulse or reaction
If no pulse is present, give five chest compressions. To achieve effective compressions, the child should be supine on a hard, flat surface. Use one hand to maintain the position of the head. With the other hand, use two fingers to trace the lower margin of the rib cage. Find where the ribs and sternum meet, avoid doing compressions in that notch. Place the heel of your hand over the lower half in the sternum, between the nipple line and the notch. Compress the chest approximately one to one and a half inches. Follow the compressions with one slow breath.
Hansen, M., ABA Journal. Jul97, Vol. 83 Issue 7, p20. 2p. 1 Color Photograph, 1 Chart.
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
The most economical method for ground improvement is aggregate piers. Before aggregate piers were used, engineers had to replace the weak soil with an engineering fill in order to use shallow foundations, but in some cases (load is very high) they had to use deep foundations, which is much more expensive. By using aggregate piers, we can now use shallow foundations in marginal soil without having to replace it. By using compacted aggregate to create stiff pier element, aggregate piers help to increase the bearing capacity, liquefaction resistance, shear strength, rate of consolidation and it reduces settlement.
Throughout the construction industry, technology plays a role to help ease the completion of a project to all of the parties involved. The amount of technology application in the industry supports the belief that technology has a positive impact on project productivity. One of the main materials used in the construction industry that surrounds us every day, in which we overlook, is concrete. Concrete is an art form, in which it takes time and talent in order for it to be used efficiently, to produce its high strength and longevity. However, the downfall of this material is that it is extremely costly and nearly impossible to form it to an aesthetically pleasing surface. In spite of this, what if I told you that there is hope? That the dream of a material made of concrete, producing the same qualities, can be formed to any shape, and used anywhere was a reality.
ement occupies approximately 50% of the mixed concrete volume and is responsible for physiomechanical properties of concrete. Cement production is essential to infrastructure and building construction, creating demands in very large quantities. Energy resources invested in the production process and resulting greenhouse gas emissions have become problematic. The cement production process has become among the world’s largest anthropogenic sources of carbon dioxide emissions, contributing to approximately 5% of global anthropogenic CO2 emissions, (WBCSD, 2009). Increased pressure is being placed on the industry to reduce CO2 emissions, owning to awareness regarding sustainability....
Concrete is one of the world’s most popular construction materials. Some six billion tonnes of concrete is produced each year in the world, making it approximately one ton of concrete for every human being per year (Fardis, 2012, p.116). However, the lifecycle of concrete does not make it the most sustainable building material at the moment. Because of limited natural resources, concerns over green house gases, and landfill problems, concrete production is being cut-back, or at least cannot be increased to keep up with population increase. In this essay, I will look at what makes concrete an unsustainable material and possible solutions to make concrete a more sustainable material.
Now a days HPC is expensive than conventional concrete. It require additional materials in some quantities as to meet specified performance.These additional materials are cement,silica fume,...
In this report, we will introduce and illustrate on precast concrete, pre-stressed concrete, ready-mix concrete, reinforced concrete, terrazzo and Urbanite in details.
Most people may not realise but concrete plays a vital part in our lives daily. It shapes and creates the built environment in which we are surrounded by, such as schools, bridges, roads, housing, hospitals, dams and so much mores. Concrete is the most used man made material in the world, averaging around 3 tonnes annually for each person. In comparison with other building materials such as wood, steel, plastic and aluminium, over twice as much concrete is used globally than any of these materials. It is the material choice of most purposes due to its strength, durability, thermal mass and its cost.