A Guide to calculate how much Ballast is needed for Concrete: Advantages & Disadvantages
Train sleepers are filled with ballast, an aggregate material that is placed beneath and around the sleepers. There are many types of gravel, sand, and coal dust available for use. In addition to stabilizing the track, ballast also facilitates drainage. As well as bearing locomotives, rolling stock, and associated tracks equipment, it supports the weight of rolling stock as well.
A train track is a combination of railroad sleepers and ballast designed to withstand the dynamic forces generated by trains or other traffic passing over it, so that it maintains its stability even after years of usage. After the sleepers are laid, the subgrade supports the rail and sleepers.
Ballast consists of a thick mixture of sand and gravel ground into small rock chunks that is used for a wide range of construction purposes, particularly to produce concrete and heavy duty work.
This material is primarily used to achieve a good running track and keep the track work in place. The ballast is normally placed on top of the subgrade. In addition to being hard-wear, having a smooth surface, carrying heavy loads and draining well, a good ballasted track should also be able to handle heavy loads.
Weightless ballast causes low strength concrete, which depends on the density and quantity of the ballast materials, as well as the concrete grade. Changing the amount of ballast will impact the concrete strength, and it depends on how much ballast is present in the concrete.
How much Concrete Strength Required for Ballast?
The strength of concrete is measured in megapascals or pounds per square inch according to the Imperial system. The strength of low strength concrete is 2000 pounds per square inch or 14 pounds per square meter.
Concrete with strength of 10000 PSI or 70 MPA is typically used for superstructures and bridges, while 5000 PSI concrete strength is commonly used for civil building structures.
You can get the foundation strength you need for concrete by mixing one part cement with eight parts ballast, or 1:8. For building structures, such as shed foundations and other structures built after the ballast is poured, 1:8 ratios will be necessary.
During the construction of pathways, driveways, patios, and slabs, the mix of cement, ballast, and water must be mixed in the required ratios and amounts in order to achieve the necessary compressive strength.
Besides ballast, cement is the main ingredient in concrete that holds the aggregate particles together, water and additives are also added as final pastes for pouring and setting.
It is commonly marketed with a five pound bag of 25 kg, making a volume of about .015 cubic meters with a weight of about 1.75 tons per cubic meter.
Ballast Cement Ratio
A concrete blend of one part cement and six parts ballast is suitable for driveways, paths, and patios, while a ratio of one part cement to eight parts ballast provides foundation strength concrete. In order to increase the strength of concrete, other materials can be kept. Steel reinforcement bars are usually found in these structures.
Ballast Cement Mix Ratio
A standard ballast cement mix ratio is 1 part cement to 5 part ballast for making concrete for the driveway and pathway. It is also possible to use a mix ratio of 1:4 or 1:6 in heavy construction.
Concrete mix ratio using Ballast
Using the concrete mix ratio 1:5 for slabs of concrete panels requires specific high strength concrete mixes. Concrete mixes containing ballast are made at a ratio of 1:6, which is ideal for driveways, paths, and patios.
Merits of Ballast
That is an advantage since it helps stabilize the track for heavy trains or equipment to pass over it. Additionally, ballast protects your railway from flooding because it has drainage properties.
The ballasts can also be placed directly on rocks without the need to remove the rocks beforehand. The underlying rock does not need to be removed if you are laying a ballasted track. The ballast's use also helps reduce the effects of external forces, increases drainage, and reduces the frequency of earthquakes.
Demerits of Ballast
In the event that ballast becomes defective, it is hard to repair. Especially when steel or manganese tracks are used & the tracks are heavy and expensive to replace. Because ballast is irregularly shaped and of different sizes, it is not possible to repair damaged rails or sleepers when they are damaged during track work.
A track assessment must be carried out before any ballasting is undertaken to determine whether ballasting is necessary. A healthy and well maintained railway system is necessary before ballasting is done.
To learn more, watch the following video tutorial.
Video Source: How2D2
Tough to Lay
The installation of ballast is more difficult than sleepers if you need to place a rail track on a slope.
Ballasted tracks require special tools and skills to smooth the ballast surface, so maintenance is more expensive than sleeper tracks.
When damaged, ballast needs to be repaired & is expensive to purchase and lay ballast.
Too much Pollution
Crushed glass and concrete, which are sometimes used for ballast, can cause noise pollution.