Mix proportioning of M25 grade concrete by replacing normal aggregate with light weight aggregate (Pumice)

. Day to day a large development in construction activities are happening. All constructions require huge quantity of concrete. All we know that conventional concrete has density 2400 kg/m 3 .This type of concrete is not at all required in all aspects. So that new era concretes are developed to solve more problems. In general Components of buildings have concrete density 2400 kg/m 3 . In high rise buildings the components are large in size. Thus, by making the components lighter, a concrete needs to have a lesser density while still retaining its adequate compressive capacity. Lightweight aggregate are employed when making the bulk of lightweight concrete. The objective of the current study is to develop lightweight concrete by replacement of pumice stone for natural aggregate for M25 grade, with pumice stone ranging proportion from 0-27.5% at 5% intervals.


Introduction
Concrete is a robust material. In many nations, due to the growing cost of raw materials and the non-stop discount of natural sources, the use of waste materials is a capability alternative within the production enterprise. Recycled materials can use after processor to required quantity, these materials proven to be effective as production substances and with no trouble meet up the design requirements. The aggregates used in structural light-weight concrete may be a combination of fractions of each lightweight coarse and quality substances and lightweight coarse fabric with the ideal, herbal great aggregate. Any combination that is adequate for replacement as lightweight has a dry free bulk density of less than 1200 kg/m 3 or a particle density of less than 2000 kg/m 3 .  3 Stated that as % of pumice quantity increases the unit weight of concrete decreases which results to form light weight concrete. Shafiq M.S et al. 4 explained that after 100% substitution of pumice stone, the split tensile strength falls about 3.36% after 28 days curing. Hayder Kadhem Adai Alfarttoosi et al. 5 said that the splitting tensile strength of concrete with pumice ranges from 5% to 10% of its compressive strength. Manoj V et al. 6 accomplished that 20% replacement of pumice stone given higher workability performance and compressive strength (87.36 MPa) with 2% nano silica substitution in cement. Abraham, A.L. and Mohan, R.P. 7 said that mechanical strength properties are increases with accumulation of polypropylene fibres to the LWC (pumice).the author recommends the optimum content of polypropylene fibres as 1.5%.N. Sivalinga Rao et al. 8 concluded that the compressive strength of light weight concrete drops abnormally. The author recommends mixing of fibres for improvement of compressive strength. GVV Satyanarayana and Mahesh 9 experimentally proved that the mechanical properties improved when fibres are added to foam concrete. Alaa M.rashad 10 concluded that the pumice aggregate increases the thermal insulation of the matrix. So that the fire resistance of matrix is increases with increase in % of pumice stone.

Cement
Cement as shown in Figure 1, is a binder constituent is used to bind sand and gravel together. Its chemical constituents interacts with water to produce extensive compounds that alters the parameters of concrete.

Fine Aggregate and Coarse Aggregate
Construction aggregate are class of coarser to medium referenced by IS:383, Aggregates are the substances on the whole used in the construction. Occupies larger volume in concrete.

Light Weight Aggregate Pumice
Pumice is made up of incredibly tiny, transparent bubble partitions of extrusive igneous rock and extremely microvesicular glass pyroclastic. When volcanic gases separate from viscous magma, several types of bubbles are formed that remain inside the viscous magma as it cools to glass. Explosive eruptions (plinian and ignimbrite-forming) frequently produce pumice as presented in Figure 2.

Water
Potable water used for mixing and curing.

Super Plasticizer
Super plasticizers (SPs), additionally acknowledged as excessive vary water reducers components used in producing excessive energy concrete.

Methodology
Properties of materials were assessed accordance of specified codes to make a mix of M25 referenced by IS:10262.

Conclusions
From the above study it was concluded that, • The unit weight of concrete is decreased with raise in content of pumice and shown table 2. • The target density achieved when 27.5% of normal coarse aggregate replaced with pumice. • The trends of light weight concrete density decrease linearly as shown Figure 3.