TP. Essai granulométrique (pratique et théorique)-Matériaux de construction

Introduction

This tutorial guides you through the process of performing a granulometric analysis of sand, a crucial test in construction materials. You will learn how to conduct the test practically and how to plot the granulometric curve using Excel. Understanding granulometry helps in assessing the quality of sand for various construction applications.

Step 1: Gather Required Materials

Before you begin the granulometric analysis, ensure you have the following materials ready:

• A sample of sand
• Set of sieves with different mesh sizes
• Balance for weighing
• Measuring container
• Stopwatch or timer
• Excel software for data plotting

Practical Tips

• Make sure the sieves are clean and dry before use to avoid contamination.
• Use a representative sample of sand to ensure accurate results.

Step 2: Perform the Sieve Analysis

Follow these steps to carry out the sieve analysis:

1. Weigh the Sample:

   • Use the balance to weigh the total mass of the sand sample. Record this weight.

2. Stack the Sieves:

   • Arrange the sieves in descending order, starting with the coarsest at the top and the finest at the bottom.

3. Sieve the Sample:

   • Pour the sand sample onto the top sieve.
   • Cover with a lid and shake the sieves for a consistent period (typically around 10 minutes).

4. Weigh the Sand Retained:

   • After shaking, weigh the amount of sand retained on each sieve.
   • Record the weights of sand retained on each sieve.

Common Pitfalls to Avoid

• Ensure the shaking is uniform; avoid over or under shaking.
• Make sure to record the weights accurately to prevent errors in calculations.

Step 3: Calculate the Cumulative Weights

To construct the granulometric curve, calculate the cumulative weight of sand retained on each sieve:

1. Calculate Cumulative Weights:

   • Start from the top sieve and add the weight of sand retained on each sieve to the total weight of sand retained from all above sieves.

2. Determine Percentage Retained:

   • For each sieve, calculate the percentage of sand retained using the formula: [ \text{Percentage Retained} = \left(\frac{\text{Weight Retained on Sieve}}{\text{Total Sample Weight}}\right) \times 100 ]

3. Calculate Percentage Passing:

   • Subtract the percentage retained from 100 to get the percentage passing for each sieve.

Step 4: Plot the Granulometric Curve in Excel

Now, let’s visualize the results by plotting the granulometric curve:

1. Open Excel:

   • Create a new spreadsheet.

2. Input Data:

   • Enter the sieve sizes in one column and the corresponding percentage passing in the next column.

3. Create the Graph:

   • Highlight your data.
   • Go to the "Insert" tab, choose "Scatter Plot" and select "Scatter with Smooth Lines".

4. Format the Graph:

   • Add axis titles and a graph title (e.g., "Granulometric Curve").
   • Adjust the scale if necessary for better visualization.

Practical Tips

• Use different colors or markers for clarity if you have multiple samples to compare.
• Label the axes clearly: X-axis for sieve size and Y-axis for percentage passing.

Conclusion

In this tutorial, you learned how to conduct a granulometric analysis of sand and plot the results in Excel. This process is essential for assessing the quality of sand used in construction. For your next steps, consider applying these techniques on different sand samples and comparing their granulometric curves to gain insights into material suitability for various construction projects.