Anomalous Method of Cement-Sand Ratio Evaluation in Hardened Cement-Mortar or Cement-Concrete

Construction or creation is a genetic human tendency and places, pyramids, houses, villas, bridges, y-overs, etc. are living examples of this inborn tendency. Civil construction is possible through proper binding materials which can bind all the construction components together. Lime has been used for centuries for this purpose but in the modern era, Portland cement has taken its place. Portland cement is widely being used to bind bricks, stones, or other construction materials in the form of cement- mortar or cement concrete. Cement-mortar or cement -concrete is made by mixing cement in a certain ratio to ne aggregates(sand) or ne and coarse aggregates together, and this certain ratio is quite important for the durability, strength, and sustainability of any civil construction. Sometimes, civil construction gets collapsed unfortunately and the ratio of cement-sand becomes the crucial point of investigation to ascertain the cause of failure. The most used method for this purpose is the acid digestion method, which is based on an insoluble percentage of silica in the cement-mortar or cement-concrete, but this method is quite lengthy having multiple stages of ltering, drying, weighing, causing multiple sources of errors. For precision, the silica percentage is being calculated through EDX/XRF nowadays. EDX/XRF method is fast as well as precise also but requires quite a costly set up as well as quite a time consuming also in respect of proper sampling and sample preparation. The present method is almost emerged as precise as the acid digestion method but gives quicker results with fewer error sources.

roofs. Properties of pure cement paste are meant to be improvised by the addition of ner nanoparticles [6]. Fine nanocrystals of CaOH2 and AFM are considered to be favorable for the strength of cement paste [7][8][9]. One of the laws that discuss the assumption of the strength of mortar is Abraham's generalization law [10] which states that mortar strength varies inversely with the water/cement ratio. Law developed to measure the strength of cement paste is stated as: -Strength= K1/K2 W/C Where K1, K2 = Constants W = mass of water C = mass of cement Implementation of Abraham's law is logical to any duration between 3 and 365 days of mortar age [11].

Current Study
The current study examined an alternative method of cement-sand ratio evaluation in hardened cementmortar or cement-concrete. Sand which is used in civil construction work has to qualify some conditions as per IS (Indian Standards) to be used as construction sand out of which the most important is grain size. The construction sand should have a grain size between 0.0075mm to 4.75mm and should not pass through 100 BSS sieve having a mesh size of 150 microns. If some part of sand passes through 100 BSS test sieve, then it should be lesser than 15%. The pit sand does not have much smaller grains than 150 microns so the sand passes in almost negligible amounts through the 100 BSS test sieve. A similar story is of the river sand but manufactured sand has that, so it has to be ascertained by proper sieving about the grading. Cement OPL and PPL both have grain sizes smaller than 150 microns, so both easily pass through the 100 BSS test sieve. For precision, the percentage of silica in the cement-mortar and cement-concrete is being calculated through EDX/XRF nowadays. EDX/XRF method is fast as well as precise also but requires a quite costly setup as well as quite a time consuming also in respect of proper sampling and sample preparation, whereas present method is almost emerged as precise as acid digestion method but gives quicker results with fewer error sources.

Procedure
A mixture of cement and pit sand ratio 1:4 is made by proper mixing. Water is added to the mixture in the proper amount to make the proper consistency of the mortar. The mortar is placed into moulds to make blocks. Settled and hardened blocks were quenched by water for seven days and dried for the next 28 days. The block was broken after drying and a small piece of almost 100gram weight is taken and kept in over at 100 degrees Celsius for 5-6 hours for complete drying. The piece is weighted and noted down. This piece is placed in a beaker as such without crushing and concentrated HCL (Hydrochloric acid) is added to fully submerge the piece. The reaction starts abruptly. The next day the beaker containing concentrated HCL and the piece are tested for completion of the reaction by adding a small amount of concentrated HCL. If reaction starts again (bubble formation) means more HCL is required, if not then HCL is su cient. Beaker is then placed on a hot plate, setting temperature 80 degrees Celsius for 2-3 hours to make sure all the soluble components of cement get dissolved in HCL. The piece is meanwhile stroked lightly and stirred with the glass rod. By stroking and stirring the piece broke into its ner components. After the complete ssure of a piece, the whole material of the beaker is ltered. During ltration, hot distilled water washing is done multiple times to remove excess acid. The ltrate is placed with lter paper (Whatman 40) in an oven at 100 degrees Celsius for 7-8 hours for complete drying, after complete drying, the material is weighed carefully and noted down, after that the material is transferred to 100 BSS test sieve for careful sieving. The remaining material on the test sieve is weighted again carefully as well as the material passed through the test sieve and noted down. Full road map of experiment is shown in Figure 2. Percentage of insoluble additives of cement = 2.694/11.822*100 = 22.788% As we have taken PPL cement for our experiment so the values of insoluble additives are also in good agreement with the theoretical value as shown in Table 1.
Observation Table   Table 1  sieving. The main difference will remain in removing the coarse aggregates before weighing through proper sieving. The IS states that sand should not contain a grain size ner than 0.075mm and also should not contain organic material, soluble salt, or materials, etc. in the light of IS guidelines, this method can be utilized for quick and almost fair results without EDX/XRF.

Methodology
Summing over 21 papers and 5 different types of calculations of current set out work, the current study has initiated possible areas for further studies about methods of cement-sand ratio evaluation in hardened cement-mortar or cement-concrete. Findings from this paper are therefore useful because the present method is almost emerged as precise as the acid digestion method but gives quicker results with fewer error sources. With a likeness and dissimilarity in mind, future studies should focus more on how to cope up with such types of lengthy methods which have multiple stages of ltering, drying, weighing causing multiple sources of errors in the acid digestion method. Figure 1 Elements present in Cement Full Road map of experiment