Prof P.R Adavi
Professor, Civil Engineering Department, M.I.T Pune
The problem of Sludge is severe with:
- The older transit mixers
- More Detention time at site
- Failure of transit Mixer
- Climatic problem
- Severe traffic jam
- Any other unforeseen situation
Approximately, 120-200 liters of water is used for cleaning of each transit mixture to remove the sludge from the blades of transit mixtures, wall and floor of the transit mixer.
- To minimize the sludge formed during transportation of Ready-Mixed Concrete from Plant to site and Back.
- To minimize the water used during removal of sludge formed in transit mixer and for cleaning of transit mixer.
- To find out alternative solution for reutilization of sludge formed dur- ing transportation of Ready-Mixed Concrete and also from the fines coming out of Sediment tanks.
|Table no 1:Production of Concrete and Sludge Formation in the month of August|
|Date||Production in Cu.m in Aug||Sludge in Cu.m in Aug||Production in Cu.m in sep||Sludge in Cu.m in sep||Production in Cu.m in Oct||Sludge in
Cu.m in Oct
Scope of project
|Figure 1: Boxplot of sludge in Cu.m for Aug||Figure 2: Histogram of Sludge in Cu.m for Aug|
Production of Concrete and Sludge Formation in the Month of August
|Figure 3: Individual Value Plot of Sludge in Cu.m for Aug||Figure 4: Scatter plot of Sludge in Cu.m Vs Production in cu.m for Aug|
Statistical Analysis of Sludge
The Regression Equation is : Sludge in Cu.m = 1.01 + 0.00866 Production in Cu.m
Interpretation of Results
|Table no 2: Basic Descriptive statistics of Sludge for the month of August|
|Variable||Mean||SE Mean||St. Dev||Variance||Coef Var||Min||Max||Range||Median||Q1||Q3|
|Sludge in Cu.m||2.038||0.193||1.076||1.159||52.81||1.42||6.0||4.58||1.6||1.51||2.17|
|Table no 3: Regression Analysis|
|Production in Cu.m||0.008661||0.002887||3.00||0.005|
|Table no 4: Analysis of Variance|
|Table no 5: Unusual Observations|
|Obs||Production in Cu.m||Sludge in Cu.m||Fit||SE Fit||Residual||St Resid|
|Figure 5: Residual plots for sludge in cu.m for Month of Aug|
There are three outliners observation 7, 9 and 26 where Residual is more than the standard Residual indicating some special cause of variation.
Thus from this result, we understand that though there is correlation between the sludge produced and the Production of Ready-Mix Concrete other factors other than Production have to be considered for formation of sludge.
Analysis of Variance (ANOVA) of Sludge Production for the Month of August, September, and October
|Figure 6: Box plot of Sludge for Aug, Sept, Oct|
The ANOVA is based on the following assumptions:
- The treatment data must be normally distributed.
- The variance must be the same for all treatments.
- All samples are randomly selected.
- All the samples are independent.
The null hypothesis will be
H0 : µ1(Sludge in Cu.m in Aug ) = µ2 (Sludge in Cu.m in Sept) = µ3 (Sludge in Cu.m in Oct)
The Alternate hypothesis will be
Ha : µ1 (Sludge in Cu.m in Aug) '"µ2 (Sludge in Cu.m in Sept) '" µ3 (Sludge in Cu.m in Oct)
|Figure 7: Indivual Value plot of sludge in cu.m||Figure 8: Residual Plot of sludge for Aug, Sept,Oct|
Interpretation of Results
Cause and Effect Diagram
By use of Analysis of variation we, tried to find out if the formation of sludge was seasonal. The study clearly showed that the formation of sludge was not seasonal i.e. there is not a statistically significant difference between the means of formation of sludge in Cu.m in the month of August, September and October i.e there is no variation in the formation of sludge with respect to time.
The cause and effect diagram helped us to identify the possible causes for formation of sludge and by studying each of the above process in depth, we would be able to improve each of the processes and how the improvement in processes could reduce formation of sludge.
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