What Is Creep In Concrete Technology?
What Is Creep In Concrete Technology?
Concrete creep can be defined as structural distortion under prolonged load. Long-term strain or tension on concrete can cause it to shift form. This deformation generally happens in the direction of the applied force.
An example is a concrete column compressing or a beam bending. Creep does not always result in concrete failure or fracture. When designing concrete buildings, creep is taken into account.
When Aggregates are influenced, they exhibit relatively little creep. It is the paste that is to blame for the creep. On the other hand, the aggregate regulates the creep of concrete by limiting the creep amplitude. The paste that creeps underweight is held back by aggregate that does not creep.
The stronger the aggregate, the more the restraining effect, and hence the less the magnitude of creep. One of the key parameters controlling creep is the aggregate modulus of elasticity.
In the case of mix proportions, one of the most critical elements determining creep is the quantity of paste material and its quality. A weaker paste structure causes higher creep. As a result, the creep rate increases as the water/cement ratio increases.
To put it another way, creep is inversely related to the strength of concrete. In general, all other elements that influence the water/cement ratio also influence creep. The age at which a concrete component is loaded will have a significant impact.
The age at which a concrete part is loaded significantly impacts the amount of creep. This is easily understood, given that gel, quality improves with time. Such gel creeps less, but a juvenile gel under strain creeps more since it is not as robust.
What is said above is not a true statement since the moisture level of the concrete varies with age and determines the amount of creep.
What Are Plasticizers In Concrete Technology?
In concrete technology, plasticizers are materials that are added to the concrete mix to increase its workability. Workability is a measure of the ease with which concrete can be placed, compacted, and finished without affecting its strength and durability.
The addition of a plasticizer to concrete will usually increase its workability without adversely affecting other properties.
In fact, the use of a plasticizer can often improve the strength and durability of concrete.
When added to a concrete mix, plasticizers are organic or a mixture of organic and inorganic compounds that lower water content for a particular degree of workability.
Plasticizers are added at a rate of 0.1% to 0.4% by weight of cement, reducing water by 5% to 15% and increasing workability from 3 to 8 cm slump.
Within the concrete mix, the cement grains absorb the plasticizer molecules, causing a change in the surface charge of the same sign, causing repulsive forces and dispersion, increasing fluidity and workability.
As their sodium salt, traditional plasticizers are lignosulphonates. Superplasticizers are polymers that are synthesized.
Sulfonated naphthalene formaldehyde condensate, sulfonated melamine formaldehyde condensate, acetone formaldehyde condensate, and polycarboxylate ethers are examples of superplasticizers.
Cross-linked melamine- or naphthalene-sulfonates, known as PMS (polymelamine sulfonate) and PNS (polynaphthalene sulfonate), are examples. They are made by sulfonating the appropriate crosslinked polymer or by crosslinking sulfonated monomers with formaldehyde.
Generally, a plasticizer is defined as a material that when added to concrete, mortar or grout, increases its workability while reducing water content, unit weight and set time
