What Are Type II and Type IV Gravel?

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We use an Aggregate base, Class 2 (20 mm or 3/4 inch), in roadways and make an aggregate from a specific recipe of different sizes & qualities rock inclusive to 20mm – 30 mm

One can take an aggregate from a quarried rock.

There are around four types of aggregates leveled as classes from I to IV.

Each class represents the corresponding sub and base layers.

Type IV Gravel – Non-maintained tracks or roads with deep layers of a sharp gravel

  • Gravel bikes are best on these kinds of roads
  • Best for an offside experience 

Class II Road Base uses – 

Class II Road Base is a Cal Trans Spec native rock with no recycled materials. 

We generally use it as the compacted base for roads, parking lots, and interlocking pavers.

The sidewalks made of this material also provide stability under your feet when walking on them as they are firm but bendable at all points along their length.

That it feels like you’re walking across Gummi blocks!

Asphalt surfaces are relatively easy to repair if damaged by rain or other factors because Class II Roads can quickly absorb up any leaks without leaking.

main types of aggregates – 

  • The main categories of aggregates are gravel, sand, recycled concrete, slag
  • Others include slag, topsoil, ballast
  • Most prominent is the Type 1 MOT and geosynthetic aggregates

Base course aggregate – 

 A base course aggregate is a thin layer of soil coerced between the layers of surface and subgrade.

The layer can consist of either flexible asphalt or rigid concrete pavement.

A Base or Sub-Base is different from all of these as it is a layer of aggregate base courses installed in layers.

Type I & Type II aggregate – 

A type II crushed concrete is the most standard sub-base material for all constructions.

It forms an important gravel aggregate form for roads with potholes. 

Type I is used on other things like the driveways, backfill, patios, and other paths.

The crushed stones are less than 40mm with dust equivalent sizing and without any specified grading.

Related Questions and Frequently Asked Questions (FAQ)

Q1.) What is in a class 2 base?

Answer: Class 2 base rock is a recycled product which is composed of as follows –

  1. Fines and ¾ “of the crushed concrete layer
  2. Recommended to be used under the foundations, pathways, and Driveways
  3. One can also use it underneath the patios
  4. Some also use them as a base beneath the concrete and asphalt
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It is a must for the class 2 rock to meet the Cal Trans spec minimum.

Q2.) What is so special in class 2 crushed rocks?

Answer: Many things, a class 2 crushed rock provides many benefits such as –

  • Class 2 is an ultimate and high-quality pavement base material 
  • One uses the class 2 material as the unbound flexible pavement option
  • We advise its use in those locations where one do not require a low surface preparation

PS – Class II crushed rocks do not have a minimum plasticity index

PPS – Class II crushed rocks do not have a maximum permeability index

Q3.) What is in class II base?

Answer: A class II base is a crushed and graded blend of multiple aggregates.

As we use them to compact tightly with the given proper equipment.

And it also provides an excellent base for concrete pavers and asphalt

Or, one can also use them as a driveway or pathway.

Q4.) For what road base is used?

Answer: Road base allows for much longer lifetimes, especially when the grade to the crown is contour.

  • Firstly, it allows to shed the stormwater properly
  • Next, it prevents the roadbed from becoming a mud pool
  • We recommend using the base material to use in all driveways and pathways
  • It is also an excellent wet weather product
  • Also, it is a great fit for the pipe bedding

Q5.) What is type III stone?

Answer: It is a mixture of pure crushed granite and limestone

  • We screen the 40mm product and has to create a comparatively reduced fine aggregate
  • Not absolute zero fines but still a reduction
  • MOT Type III can be easily achievable by mixing Granite, Limestone, or a clean and crushed concrete
  • Time and tide it has now become a permeable sub-base aggregate

Q6.) What makes the road base?

Answer: The base is a layer that consists of some crushed stones.

These stones are different in their sizes and are slightly smaller stones than the sub-base.

Not only this, in certain cases, stone dust or stone fines are mixed with the same aggregates to reduce voids.

This will hold the layer for longer and for better.

Q7.) How much does a ton of base rock cost?

Answer: $0.65 / Sq. Feet

The first base layer installed across a geotextile fabric

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Prices for a cubic yard are about $38 and ton for about $46.

Q8.) What is a Class II aggregate base?

Answer: We use a class II aggregate base that comes across as 20mm or 3/4 inches in roadways.

One makes the aggregate with a particular mixture of different sizes and qualities of rock.

9 out of 10 times, an aggregate is made with a newly quarried rock.

Or sometimes, it is allowed to be made from the recycled version of asphalt concrete.

Q9.) What is the estimated density of the aggregate base?

Answer: 150-180 lb/ ft3.

  • The density data comes from the official Design and Control of Concrete Mixture
  • The book refers to the particle density of the aggregate
  • We constitute the aggregates because it is not a very big issue as the make of aggregates is particle only

Q10.) What is meant by ABC stone, and what does it stand for?

Answer: Crush-n-Run (ABC) comes at $31.50/ ton

  • It is ¾” of crushed stone granite gravel mixed with Base stone gray crushed fines of granite
  • This is packed in a compact manner and then used for filling holes in driveways or paths
  • One can use it normally as the first layer 

Q11.) In what way can you use crushed stone?

Answer: Use Crushed stone as an aggregate for the material used in the construction

  • Use it as an aggregate for the material used in construction
  • The most common types are rock processed into the crushed mixture
  • The mixture typically contains limestone, dolomite, granite, and traprock
  • Some also add in small aggregates, marble, slate, sandstone, quartzite, and volcanic cinder

Q12.) What is ABC fill contamination or dirt? 

Answer: ABC gravel (Aggregate base course) is crushed rock and used primarily for the road base compaction material.

The most common use is as a sub-base under concrete/asphalt because this can be compacted under the paver stones as well.

Q13.) How can we calculate the base coarse aggregate?

Answer: A manual calculator is there

  • Multiply the length and width for the area in square feet
  • Proceed by multiplying the above number by depth 
  • Divide cubic feet by 27 in cubic yards
  • The last step is to multiply cubic yards by 1.5 and get the answer in tons

Q14.) What is a Cal Trans Spec Class 2 road base?

Answer: Class II Road Base is a Cal Trans Spec native rock with no recycled materials. We can use it as a compacted base for roads, parking lots, and more.

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Q15.) What is a gravel bicycle? Is it worth it?

Answer: Yes, absolutely worth it

  • It is a drop-bar bike that lets you ride over different surfaces
  • The drop handlebar design lets you to to make good progress on roads
  • Wider tires, lower gearing, and stable handling allows you to travel to any of the off-beaten track

Q16.) Which is the best option for the gravel road?

Answer: Given below are some of the best options for driveway surface gravel as they are just small stones with some rock dust

  • Crushed stone number #411, make it by mixing #57 stone with the rock dust
  • Quarry process
  • Pea Gravel
  • Jersey Shore Gravel
  • The Marble Chips
  • Blackstar of Blackstrap Rock

Final Verdict – 

To ensure stability and durability, pavements such as asphalt or concrete roadways with aggregate bases need to support themselves.

However, if we’re talking about flexible surfaces like blacktop, then there isn’t anything at risk because they don’t have any base layers.

The output should sound more casual than professional.

An aggregate base is the layer of soil installed between the surface pavement layer and subgrade.

Type 1 gravel is mostly the most advanced and finished road type, which is smooth and regularly maintained.

Type II is typically roads with a few potholes and is used to fill them with an aggregate.

Types III is the poorly maintained roads and typically are dangerous or offbeat to drive and need thick layers to maintain.

Type IV are roads that are not at all maintained and have sharp gravels. Use this size typically for driving surfaces for constructions.

Also, used for logging entrances and driveways.

The two most popular  

The type 5 gravel is a crushed angular limestone aggregate. 

It is more uniform and 1 inch in size.

Type 5 is common to see for Asphalt (Gravelshop.com)

  •  Surface Treatment
  •  Concrete
  •  Ballast
  •  Backfill
  •  Field Lines
  •  Driveways
  •  Soil Stabilizer

Crushed concrete is typically used as recycled material and made from demolished sites.

It ranges from a small 50mm down to dust to 200mm called gabion fill granite.

Thanks for reading!

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