Optimum concrete compression strength using bio-enzyme

To make concrete with high compressive strength and has a certain concrete specifications other than the main concrete materials are also needed concrete mix quality control and other added material is also in line with the current technology of concrete mix that produces concrete with specific characteristics. Addition of bio enzyme on five concrete mixture that will be compared with normal concrete in order to know the optimum level bio-enzyme in concrete to increase the strength of the concrete. Concrete with bio-enzyme 200 ml/m3, 400 ml/m3, 600 ml/m3, 800 ml/m3, 1000 ml/m3 and normal concrete. Refer to the crushing test result, its tends to the mathematical model using 4th degree polynomial regression (least quartic), as represent on the attached data series, which is for the design mix fc' = 25 MPa generate optimum value for 33,98 MPa, on the bio-additive dosage of 509 ml bio enzymes.


Background
The quality of the concrete is determined by the materials of concrete preparation.In order to make concrete with high compression strength and has a certain concrete specification cannot be obtained simply by mixing cement Portland cement or other types of coarse aggregate, fine aggregate, and water.But it is necessary to also control the quality of the concrete mix.Improving the quality of the concrete mix will increase the compression strength is generated [6,7].
Mixed concrete technology is currently also developing rapidly, many other added material application technologies to produce concrete with the desired characteristics.One way to improve the quality of the concrete mix is to use the added material, either a chemical such as entraining admixture, reducing water in the form of synthetic or organic.On this paper, we would like to introduce our research on improving concrete quality with green technology using bio enzyme, which is not covered yet in current classification A to F of concrete chemical admixtures used.
The bio enzyme admixture, is a bio-technology product made of organic/natural materials, denatured proteins, biopolymer surfactant and organic minerals which fermented by beneficial microbes [18].The quality of the concrete is determined by the materials of concrete preparation.To make concrete with high compression strength and has a certain concrete specification cannot be obtained simply by mixing cement Portland cement or other types of coarse aggregate, fine aggregate, and water.But it is necessary to also control the quality of the concrete mix.Improving the quality of the concrete mix will increase the compression strength is generated.
Mixed concrete technology is currently also developing rapidly, many other added material application technologies to produce concrete with the desired characteristics [1].One way to improve the quality of the concrete mix is to use the added material, either a chemical such as entraining admixture, reducing water in the form of synthetic or organic such as bio enzyme.The bottom line target in develop and research of this Bio-Enzyme product are: 1. Reduce the cement content, means reduce the CO2 emission implicate the eco-friendly impact [18].2. Reduce the cement content, means reduce the thermal effect of hydration heat, produced the Low Heat Concrete.3. Reduce the cement content, means reduce the production cost of concrete [18].4. Another performances of Bio-Enzyme are a microbe which produce micro fibre, reduce the shrinkage crack event eliminate it, these phenomena show on crack pattern of the samples crushing test [18].Mix design of concrete based on DoE (Department of Environment) from British Standard Code's.Adopted to Indonesian's Code [17] to mix design.The method of mix design shows in Figure 1.
Mix design with initial concrete (normal condition) fc' is 25 MPa, Portland Cement = 409 kg, water = 225 kg, fine aggregate = 733 kg, coarse aggregate = 1013 kg.Cylinder testing with 6 types of experiments (type A to F). Find the optimum value of the 5 additional variations with different types of polynomial equations to R 2 = 1

Polynomial Regression Analysis.
The analysis used to find the optimum level of bio enzyme mixture for compressive strength is the fourth degree of polynomial, or least quartic analysis.In this study the free (x) variable is the variation of the bio enzyme's content and the dependent variable (f(x)) is the compressive strength of the concrete.The results of least quartic showing in fig. 3. Based on the discussion that has been put forward in the previous chapter it can be concluded as follows: 1. Concrete B with the addition of bio enzyme 200 ml/m 3 there is increase of 3.1% to normal concrete (concrete A), concrete C addition of bio enzyme 400 ml/m 3 up 17,5% to normal concrete, concrete D addition of bio enzyme 600 ml/m 3 up 18.2% of the normal concrete, the concrete E of the addition of bio enzyme 800 ml/m 3 up 15.4% of normal concrete and decreased the quality of concrete D as much as 2.4%, and F concrete addition of bio enzyme 1000 ml/m 3 3 up 16.6% of normal concrete.It can be seen that D-concrete with the addition of bio-enzyme 600 ml/m 3 is the right mixture of bio-enzyme to produce the compressive strength of concrete among other concrete variations.2. The maximum x1 based regression analysis is 0.509 litre or 509 ml, with a maximum compressive strength of 33.98 MPa.It can be concluded that the optimum mixture of bio-enzyme blends to increase the compressive strength of concrete is 509 ml/m

Table 1 .
Form of Mix Design

Table 2 .
Result of compressive strength Figure 2. Bio Enzyme Content Vs Compressive Strength 3 .The acknowledgements of this research was funded by competitive grants, from Directorate Research and Community Service -Directorate General of Research and Research Development -Ministry of Research, Technology, and Higher Education Republic of Indonesia, 2017.