Generally, the most consistent characteristic of concrete is its aptitude to continually change, creating a need for troubleshooting. Thanks to constant variability in raw ingredients and the science of advancing a mix from design stages to a desired finish, dialing in the perfect product can be extremely frustrating and time consuming.
Etymology[ edit ] The word concrete comes from the Latin word "concretus" meaning compact or condensed the perfect passive participle of "concrescere", from "con-" together and "crescere" to grow. Prehistory[ edit ] Small-scale production of concrete-like materials dates to BC, pioneered by the Nabataea traders or Bedouinswho occupied and controlled a series of oases and developed a small empire in the regions of southern Syria and northern Jordan.
They discovered the advantages of hydraulic lime, with some self-cementing properties, by BC. They built kilns to supply mortar for the construction of rubble-wall houses, concrete floors, and underground waterproof cisterns.
They kept the cisterns secret as these enabled the Nabataea to thrive in the desert.
German archaeologist Heinrich Schliemann found concrete floors, which were made of lime and pebbles, in the royal palace of TirynsGreece, which dates roughly to — BC.
Its widespread use in many Roman structuresa key event in the history of architecture termed the Roman Architectural Revolutionfreed Roman construction from the restrictions of stone and brick materials.
It enabled revolutionary new designs in terms of both structural complexity and dimension. Laid in the shape of archesvaults and domesit quickly hardened into a rigid mass, free from many of the internal thrusts and strains that troubled the builders of similar structures in stone or brick.
First, its mix consistency is fluid and homogeneous, allowing it to be poured into forms rather than requiring hand-layering together with the placement of aggregate, which, in Roman practice, often consisted of rubble.
Second, integral reinforcing steel gives modern concrete assemblies great strength in tension, whereas Roman concrete could depend only upon the strength of the concrete bonding to resist tension.
The Baths of Caracalla in Rome are just one example. Many Roman aqueducts and bridges, such as the magnificent Pont du Gard in southern France, have masonry cladding on a concrete core, as does the dome of the Pantheon.
Middle Ages[ edit ] After the Roman Empire, the use of burned lime and pozzolana was greatly reduced until the technique was all but forgotten between and the 14th century. From the 14th century to the midth century, the use of cement gradually returned.
The Canal du Midi was built using concrete in This third Eddystone Lighthouse pioneered the use of hydraulic lime in concrete, using pebbles and powdered brick as aggregate. His son William continued developments into the s, earning him recognition for the development of "modern" Portland cement.
The first concrete reinforced bridge was designed and built by Joseph Monier in . Composition[ edit ] Many types of concrete are available, distinguished by the proportions of the main ingredients below.
In this way or by substitution for the cementitious and aggregate phases, the finished product can be tailored to its application. Strength, density, as well as chemical and thermal resistance are variables.
Aggregate consists of large chunks of material in a concrete mix, generally a coarse gravel or crushed rocks such as limestoneor granitealong with finer materials such as sand. Cementmost commonly Portland cementis associated with the general term "concrete.
One of the most familiar of these alternative cements is asphalt concrete. Other cementitious materials, such as fly ash and slag cementare sometimes added as mineral admixtures see below — either pre-blended with the cement or directly as a concrete component — and become a part of the binder for the aggregate.
To produce concrete from most cements excluding asphaltwater is mixed with the dry powder and aggregate, which produces a semi-liquid slurry that can be shaped, typically by pouring it into a form.
The concrete solidifies and hardens through a chemical process called hydration. The water reacts with the cement, which bonds the other components together, creating a robust stone-like material.Our Mission.
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Proportioning Concrete Typical mixing procedure: 1. Clean mixer 2. Add aggregates and mix for 2 minutes 3. Add cement and mix for 2 minutes 4. Add ½ of the mixing water and mix for 2 minutes 5. Add remaining mixing water and mix for 5 minutes (pay close attention to the concrete in the back of the mixer and make sure that.
Methods of Proportioning Cement, Sand and Aggregates in Concrete Proportioning of concrete is the process of selecting quantity of cement, sand, coarse aggregate and water in concrete to obtain desired strength and quality.
Concrete Mix Proportioning Using Micro Silica Proceedings of 4 th IRF International Conference on 19 April , Cochin, India, ISBN: reactions. Because of its chemical and physical properties, it is a very reactive pozzolana. of mix proportioning for high-performance concrete (HPC) based on estimating individual amount of concrete ingredients are presented and discussed.
Finally, experimental results of high-performance fine constituents of concrete mixes. Evolutions in concrete mix proportioning procedures are taking Various concrete mix proportioning method make the provision place since long.
Abram’s w/c ratio versus strength law is a regarding grading and size of aggregate.