Although ready-mix concrete may be easier to use for those with no knowledge of home repairs, all concrete is made with sand and gravel aggregate. Concrete made by hand lets you add ingredients such as pigments or decorative gravel. When mixing concrete by hand, it is important to get the right mix of wet and dry ingredients.
The dry ingredients of the concrete are commonly 3 parts gravel or coarse aggregate, 2 1/2 parts sand and one part of Portland cement. All these ingredients are available in individual bags in the places where ready-mix concrete is sold. When mixing concrete by hand, you must first mix the dry components with a shovel in a large container such as a truck or large bucket. Make sure your dry and fine ingredients like sand and cement are well mixed and the gravel is incorporated. Always reserves a small amount of dry concrete mix to add to it if you have been very watery.
An additive used in the field of concrete is called combustion ash. This is an aggregate of fine particles such as cement concrete helping to mix and flow. Other additives include plasticizers that cause the concrete to flow, chemical additives to prolong the drying time and powdered pigments for coloring concrete. Decorative stones or crushed glass can be incorporated into the concrete to give it a unique style.
When concrete is mixed, always uses the least amount of water to cement a cohesive material. More water will make concrete more prone to cracking and volume reduction, and takes hardness when compressed. To find the correct ratio of cement to water, you must calculate the weight of the water and the weight of the cement. At a minimum, the concrete precise proportion of 20% water to cement, or a pound (0.45 kg) of water for every four pounds (1.8 kg) of cement should be used in the mixture. Most manufacturers use a specific proportion between 35% and 40%.
Once the dry ingredients are mixed, make a wheel in the center of the mixture. Slowly add water in the middle of the ingredients and thrown dry ingredients into the center for mixing. Keep adding water to the cement until it holds its shape and only see a little water. When concrete is perfectly hydrated, concrete made with ridges should hold the blade in it.