Oga, I have done casting and filling with laterite, do I need to use hardcore again or bricks before german floor. Is thought is just ramming the laterite.
Hardcore application in the building process is also as important as any of the key stages . Hardcore is reffered to as some measures of large aggregates of stones used as part of the foundation in a construction project. To simple put is bigger aggregates of what you call granites on site. Though some uses broken blocks /bricks, these are however not recommended because of their strenght, people only use them to save cement during casting of oversite/german concrete which is not advisable.
Hardcore is applied after you have filled the internal part of your foundation with laterite or sharpsand as the case may be, rammed and ready to apply iron rods/wire mesh and concrete. In the usage of hardcore, the textbook application is as shown in the image 1 below, there is a space entirely left for the hardcore as specified by the professional before the space for the concrete, this is standard or you call it textbook application, but getting the accurate thickness during construction for portion of concrete is not always common because of crude method of construction, level of skill of the builder and the settlement pattern due to nature of soil. So what most people do onsite is as shown in image 2-the hardcore takes a portion of the concrete space so you only needs to fill the remaining parts with concrete.(Is not what is recommended but is what most do)
(1)Hardcore strengthens or solidifies the base which the german concrete will sit on, thereby helps in resisting pressure of dead and live loads on the ground floor.
(2}It gives good base for building
(3)Is also part of foundation
(4)In the image 2 type of application, it helps to save cost of construction, the volume occupied by the hardcore if it were to be concrete it would have cost more.
(5)Is a gap between the german floor /oversite concrete and the earth so it helps to reduce movement of water up to the ground floor
(6)The air in between the hardcore if there is any will also help to reduce movement of water.
(7)In case of image 2, it reduces the time of casting because you are using lesser volume of concrete to when you are casting the entire mass.