In order to get a solid foundation for a suburban or urban building, it is necessary to correctly make the foundation. The strength of concrete will only be sufficient when all proportions of the mortar for the foundation are correctly calculated.
Proportions of components depending on working conditions and materials
Depending on which cement will be used to prepare the mortar, the ratio of aggregates - sand, gravel or gravel - changes. The number of components differs depending on the quality of the soil itself - whether it is dry or wet.
With manual kneading, the weight of the components is most often measured in buckets. A standard 10-liter bucket holds about 15 kg of sand, 14 kg of cement and about 16 kg of crushed stone. The total amount of the initial volume of the dry mix decreases after the batch by almost a third, this must be taken into account.
Do not change the ratio of components in the cement mortar for each new batch. It is enough to make a solution for the foundation (the proportions remain the same!) In the same way as the previous time. Usually use the recommended standard values. 1: 4: 6.5 are considered standard for M500 cement, where 1 is part of the cement, 4 is sand, 6.5 is crushed stone. The ratio of sand and gravel when using cement M400 - 1: 3,5: 6.
In dry soil, to reduce the cost of work, secondary crushed stone can be used as a loose aggregate - the so-called fragments of brick and old concrete. Non-condition left during the production of concrete, or fragments of bricks are brought to the desired size using a stone crusher or a conventional sledgehammer.
The proportions of the solution for the foundation, installed in soils of high humidity, are different. For cement M500 - 1: 3.4: 5.8, for M400 - 1: 3: 5.5, respectively.
Before mixing concrete, it is advisable to specially prepare bulk materials: select large pieces from rubble, rubbish, rinse out of the hose if there are a lot of clay impurities. Sift the sand to prevent ingress of foreign matter. You can use liquid soap or shampoo as a plasticizer to increase the plasticity of the solution, or you can buy a special additive.
The proportions of the mortar for the foundation do not always correspond to standard values. As you knead, it may sometimes be necessary to introduce an additional component. It is necessary to focus on the consistency of the solution. It should pour out of the tank, like thick sour cream.
They are engaged in a cement mixture after the installation of formwork and reinforcement is completed, otherwise it will have time to thicken. It is also worth separately calculating how much solution to knead at a time. Unused solution is suitable only as secondary crushed stone.
With the increase in the grade of cement from which the cement mortar is made, the proportions for the foundation of the remaining components decrease. It is believed that cement of grade lower than M400 is not practical for foundation work.
The proportions of the mortar for the foundation do not change depending on the time of year. But if work with the mortar is carried out at low temperatures, then antifreeze additives are added to the cement mixture . When calculating how many additives should be introduced into the cement mortar, the amount of cement and the temperature conditions during which concrete work is carried out are taken into account.