What You Should Know About Concrete Slump
Concrete slump is a phrase used to help clarify the particular working conditions of a given concrete mix. Without proper knowledge of concrete slump, you may find yourself with concrete that doesn't pour, spread, or cure the way it should. Whether you work in the construction industry, or are simply a curious amateur, if you would like to improve your knowledge of concrete, read on. Here is what you need to know about concrete slump.
Workability
Not every batch of concrete will possess the same workability, which is governed by such factors as the ingredients and ratios used in the mix, as well as environmental and pouring conditions. Workability may refer to three particular aspects of the concrete's behavior. First of all, it may express the ease and fluidity of the concrete as it its poured.
Workability also designates the degree of resistance to segregation, which is the undesirable separation of the concrete's core ingredients as its cures. Lastly, workability helps to indicate the strength the concrete will exhibit when being compacted. As you can imagine, accurately measuring each of these things in order to determine workability can be difficult. Luckily, that's where slump value comes in.
Concrete Slump
The slump value of a particular concrete is the best way to characterize its workability. Slump value is generally calculated on a batch by batch basis by a concrete manufacturer. Likewise, it should be checked again at the work site, to ensure that no changes have taken place in the meantime.
The slump value designates the extent to which a cone of fresh concrete will collapse underneath its own weight. Determining slump value can be accomplished by means of a relatively simple test. Several layers of concrete are added to an upside down cone. This mold is then flipped over and removed. The concrete's height is measured immediately. The difference between this measurement and the height of the cone itself is the slump value.
Slump Loss
As noted above, the slump value of a particular batch of concrete is not a static thing. In other words, slump tends to change as time goes on, generally as the result of water evaporating outward. This causes the concrete to grow stiffer. In other words, the slump value decreases. This phenomenon is known as slump loss.
Slump loss means that the concrete's workability will decrease. As a result, it will be both harder to spread, and potentially weaker once it has cured. Avoiding slump loss usually involves adding small amounts of water to the concrete mix, as well as keeping it properly covered to minimize the amount of evaporation occurring.
For more information, talk to a professional like ACPLM.