When the fines content in sand are excessive, there is the need to add more water to the concrete mix in other to improve the workability. That is fine particles such as clay and cement interact with water in a physiochemical state which leads to more absorption of water than that of fine and coarse aggregates.
Too much sand will mean that the mix will be weak, and the elements could damage the finished surface. To improve the working properties and durability of the concrete and mortar, you can add extra materials. These materials could be lime, plasticiser or other building chemicals.
Concrete is rated on a system that indicates the strength of the mix after it's cured for approximately a month. To make the concrete stronger, add more cement or less sand. The closer you bring the ratio to an even one-to-one of sand to cement, the stronger the rating becomes.
The closer you bring the ratio to an even one-to-one ratio of sand to cement, the stronger you will make the concrete. On the other hand, if you push the ratio in the other direction you will get a product that has slightly less strength.
In terms of the ratio for concrete, it depends on what strength you are trying to achieve, but as a general guide a standard concrete mix would be 1 part cement to 2 parts sand to 4 parts aggregates. For foundations, a mix of 1 part cement to 3 parts sand to 6 parts aggregates can be used.
The usual range employed is between 9.5mm and 37.5mm in diameter. - Fine aggregates are usually sand or crushed stone that are less than 9.55mm in diameter. Typically the most common size of aggregate used in construction is 20mm. A larger size, 40mm, is more common in mass concrete.
What is the ideal cement mix ratio? As per the experts, the safest cement mix ratio for all kinds of concrete used in different construction purposes is 4:2:1. It means 4 parts of crushed stones mixed with 2 parts of sand and 1 part of cement will create the ideal cement mix to prepare concrete for all purposes.
And as we mentioned above, you can technically use sand under some concrete slabs, such as walkways, but you'll almost always need a stronger material for driveways and roads.
Quick Facts On Cement Mix Ratios
Too much sand, gravel or both reduces workability and usually requires adding more water, weakening the mix. For a smooth surface, your safest bet is to use less aggregate and or smaller/smoother aggregate in your concrete mixture ratio.
BULKING OF SAND:-
This results in the increase of the volume of sand. Excessive presence of moisture content in the sand makes concrete to less durable and lose its strength. Remember, excessive presence of moisture content increase the workability of concrete but loses its strength.
Optimal mixing time is important for strength. Strength tends to increase, with mixing time, up to a point. However, over-mixing causes excess water evaporation and the formation of fine particles within the mix. This weakens the concrete and makes it harder to work with.
You can add more Portland cement to bagged concrete to make it stronger. You can also add hydrated lime.
If too little cement is used, the aggregate mix will not cohere and the concrete will crumble under pressure. Considering the effects of too much or too little cement, it is best to make cement one-seventh of the mix ratio.
Sand Is An Essential Ingredient In Concrete
The rough exterior provides more surface area for other materials like water and cement to bind to. This makes coarse sand such as concrete sand much better to use in construction where stronger material bonds are needed to create more durable and longer-lasting concrete.
Dry delivers more shine
It will provide a much higher level of light reflection and a classier-looking floor. Dry polishing will also always work better on a soft concrete floor. Soft concrete can wear even the hardest diamond bonds out far faster than expected. This causes job costs to surge and profits to dwindle.
It is possible to make concrete with beach sand and shells as aggregate, provided the materials are clean and are properly graded, though it may not prove economical. Because shells are usually flat and sharpedged they make concrete with poorer workability than more commonly used gravel or crushed stone.
To prevent cracking and crumbling, concrete patios need to be built on solid, well-drained soil. If you live in a region with lots of clay in the soil, you will need to dig down further and backfill with layers of compacted sand and gravel.
Sharp sand is usually preferred over builders sand when making concrete because of its grittier consistency, however you can add a coarser aggregate to your builders sand if you don't have any sharp sand to make concrete.
One bag of cement (50 Kgs) has to be mixed with 115 kgs of Sand, 209 Kgs of aggregate and 27.5 kgs of water to produce M20 grade concrete.
A mixture of cement, gravel, coarse and water is called concrete. Mortar is composed of sand and cement.
If the ambient temperature is too low, the hydration of the cement will drastically slow down or completely stop. Cold weather slows down the setting process or stops it completely, negatively impacting the concrete's strength gain.
Using warm water
As an essential ingredient in any concrete mix, water plays an important role in the curing process and can affect curing times in a number of ways. For example, if you use slightly warmer water in your concrete mix, you can encourage a quicker reaction and, in turn, a quicker curing time.
Modulus of Elasticity is directly related to strength. A high strength may cause the concrete to be more prone to cracking (serviceability concern).
Moist curing is a common method of concrete curing. It involves wetting the concrete slab often with water (5-7 times per day) for the first 7 days. This method ensures your concrete slab will be extremely strong and durable, because it allows the moisture to evaporate slowly, preventing cracks and shrinks.