Understanding Soil Particle Retention on the #200 Sieve

Understanding Soil Particle Retention on the #200 Sieve

When diving into the fascinating world of soil mechanics, you might have encountered the question: If a soil particle is retained on the #200 sieve, what type of soil is it likely to be? The options are a bit of a head-scratcher if you’re not familiar with the basics—so let’s break it down together.

What’s up with the #200 Sieve?

First off, what’s this whole sieve thing about? The #200 sieve is like a fine mesh net in the world of soil testing. It has mesh openings that are 0.075 mm in diameter, which means it's designed to catch larger soil particles while letting the small stuff slip through. If a soil particle gets caught on this sieve, it’s telling us something very important—the size of the particle!

What Are We Retaining?

So, if our particle is retained on the #200 sieve, it can’t be just any old soil, right? According to the question's options, those lucky winners are either:

• A. Clay/Silt

• B. Sand/Gravel

• C. Silty Sand

• D. Rock

Here’s a little insight: clay and silt, being the tiny underdogs of the soil family, are smaller than 0.075 mm. They can slide right on through that #200 sieve like it’s a VIP entrance they’re all too familiar with! What does that leave us with? You guessed it—bigger players like sand and gravel, which are the real contenders for our answer.

Why Sand/Gravel Fits the Bill

Now, let's dig a little deeper into why B. Sand/Gravel is the correct choice. When we talk about sand and gravel, we’re looking at coarse particles. These types of soils are crucial in various engineering applications, especially when it comes to constructions like roads, foundations, and drainage systems. They don’t just sit there; they facilitate water drainage and provide a stable base for structures.

Once a soil particle exceeds the #200 threshold, it essentially shifts gears into the coarse-grained category, aligning perfectly with sand and gravel characteristics. This is vital knowledge for anyone preparing for the PE Civil exam, as understanding the behavior of these soil types can make or break your decisions in civil engineering projects.

What About Silty Sand?

You might be wondering, what about options like C. Silty Sand? Well, silty sand is an interesting mix because it contains silt-sized particles, which would also pass through the #200 sieve. So, if you see a soil mix described as silty sand, it doesn’t retain all particles, meaning it’s not quite right for our situation.

The Bigger Picture

In conclusion, retaining a soil particle on the #200 sieve gives us a clear indicator—it's sand or gravel we’re looking at. Understanding these distinctions can help you not only in answering exam questions correctly but also in practical applications where soil behavior can impact stability and design.

This knowledge enriches your engineering toolbox, allowing you to apply these principles when assessing soil for future projects. Think about it; you're not just studying for an exam—you're paving the way for better civil engineering practices that can lead to safer and more efficient structures.

So, whether it's enhancing your understanding for the PE Civil exam or boosting your confidence on the job site, keep these concepts in mind as you journey through the world of civil engineering. Here's to building a sturdy foundation, both literally and metaphorically!