WHAT IS THE RIGHT MIXTURE OF CONCRETE FOR HOUSE CONSTRUCTION???
Concrete is the most important material used in the construction extensively in all types of Building construction.
It is most durable material used during the whole construction process.
• The process of selecting suitable ingredients of concrete and determining their relative amounts with the objective of producing a concrete of the required, strength, durability, and workability as economically as possible, is termed the concrete mix design.
• The Strength of the concrete mixture which is generally considered to be their properties, depending on many factors e.g. quality, quantity of cement water, and aggregates, not alone that it also depends on the batching and mixing, placing compaction and curing
Let us see the Requirements of concrete mix design
During the process building construction we should to widely know about the selection and proportioning of the Mix and the requirement.
These are decided with the few considerations of the building and are going to be constructed – House Construction, Building Constructions, Or Renovations,
a) The minimum compressive strength required fromstructural considerationof a house required for the construction.
b) The adequate workability necessary for full compaction with the compacting equipment available during the construction of house.
c) Maximum water-cement ratio and/or maximum cement content to give adequate durability for the particular Building Construction.
d) Maximum cement content to avoid shrinkage cracking due to temperature cycle in mass concrete will help us in constructing the strength to the house.
Let us talk technically a certain things where the people needs to know while planning for the construction
In order to calculate or find the right amount of cement, sand and aggregate required in 1m3 of Concrete
Even though Many of Us use the Same Standard Concrete Mix for the Building Structure – House Construction, We have different types of Concrete Mixes. Nominal Mix and Design Mix.
In the past, the specifications for concrete in the Construction prescribed the proportions of cement, fine and coarse aggregates. These mixes of fixed cement-aggregate ratio which ensures adequate strength to the Construction of the Building. These offer simplicity and under normal circumstances, have a margin of strength above that specified. However, due to the variability of mix ingredients the nominal concrete for a given workability varies widely in strength in the Construction process.
In these mixes the performance of the concrete is specified by the designer of the Building
• House Construction but proportions the mix are determined by the producer of concrete, except that the minimum cement content can be laid down.
• This is most rational approach to the selection of mix proportions with specific materials in mind possessing more or less unique characteristics. The approach results in the production of concrete with the appropriate properties most economically. However, the designed mix does not serve as a guide since this does not guarantee the correct mix proportions for the prescribed performance.
• For the concrete with undemanding performance nominal or standard mixes (prescribed in the codes by quantities of dry ingredients per cubic meter and by slump) may be used only for very small jobs, when the 28-day strength of concrete does not exceed 30 N/mm2. No control testing is necessary reliance being placed on the masses of the ingredients.
This is the Mix which we widely use in present day for all the Constructions.
• The nominal mixes of fixed cement-aggregate ratio (by volume) vary widely in strength and may result in under- or over-rich mixes. For this reason, the minimum compressive strength has been included in many specifications. These mixes are termed standard mixes.
• This Mix used for construction is IS 456-2000 has designated the concrete mixes into a number of grades as M10, M15, M20, M25, M30, M35 and M40. In this designation the letter M refers to the mix and the number to the specified 28 day cube strength of mix in N/mm2. The mixes of grades M10, M15, M20 and M25 correspond approximately to the mix proportions (1:3:6), (1:2:4), (1:1.5:3) and (1:1:2) respectively.
GRADES OF CONCRETE
• Grade of concrete for Construction is defined as the minimum strength the concrete must possess after 28 days of construction with proper quality control of the building. Grade of concrete is denoted by prefixing M to the desired strength in MPs.
• Nominal mixes for grades of concrete such as M15, M20, and M25 are generally used for small scale construction.
• Large structures have high strength requirements, thus they go for higher grades of concrete such as M30 and above. The mix proportions of these concretes are based on mix design.