Guide

Flex Base vs Crushed Concrete: What’s the Difference?

This is the most common base-material question in Texas site work, and it is confusing because the two things being compared are not the same kind of thing. Flexible base is a specification. Crushed concrete is a material that can meet it. Here is what TxDOT Item 247 actually separates, when recycled concrete is the right call, when your plans will not allow it, and how to order either one.

Crushed concrete and flexible road base aggregate

Key takeaways

Flexible base is a spec, not a material. In Texas it is TxDOT Item 247, which defines several material types and several grades.
Crushed concrete is a material, and Item 247 recognizes it as one of the base material types it allows.
So the honest comparison is not “flex base or crushed concrete”, it is which material type your plans call for, most often crushed stone (Type A) or crushed concrete (Type D).
Grade sets the numbers. Plasticity Index, Liquid Limit and gradation caps come from the grade, and Grades 1 and 2 are the tight ones (PI 10 or less, LL 40 or less).
Crushed concrete usually prices lower and is the recycled option. Many public and spec jobs still call for crushed stone, so the plan decides, not the price.
Both compact into a stable, load-bearing base. The difference shows up in what a spec will accept, not in whether the material works.

Why the question is confusing

Ask five crews what flex base is and you will get answers that describe crushed limestone. That is not wrong in practice, because crushed limestone is what most Texas yards hand you when you order flex base, but it is wrong in principle, and the difference matters the moment an engineer writes a spec.

Flexible base is the compactable structural layer under a pavement, drive or laydown yard, and in Texas it is governed by TxDOT Item 247. Item 247 does not name one rock. It defines a family of acceptable material types and a set of grades, and it explicitly allows recycled crushed concrete as one of those types. Road base and crushed concrete from Soil Depot are both supplied against that spec.

So a plan sheet never says “use flex base or crushed concrete”. It says something closer to “Item 247, Type A, Grade 1-2” or “Item 247, Type D”. Read that line before you price anything, because it is the line that decides whether recycled material is even on the table.

Attribute	Crushed stone flex base (commonly Type A)	Crushed concrete (commonly Type D)
What it is	Virgin quarried stone, in Texas most often crushed limestone, produced and graded to the spec	Reclaimed concrete crushed and graded back to a comparable base gradation
Source	A quarry	Demolition and reclaimed concrete, processed
Governing spec	TxDOT Item 247, Flexible Base	TxDOT Item 247, Flexible Base
Typical uses	Pavement base course, spec roadway work, public jobs	Sub-base, stabilized access, laydown yards, temporary haul roads, and base course where the plans allow it
Relative cost	Higher	Usually lower
Recycled content	None	Yes, this is the recycled option
Compaction	Compacts to a stable, load-bearing base	Compacts to a stable, load-bearing base
Where it gets ruled out	Rarely ruled out, usually ruled out only by budget	Ruled out where the plans specify virgin stone, or where the job restricts recycled material
How sold	By the ton, bulk, delivered	By the ton, bulk, delivered

What TxDOT Item 247 actually separates

Item 247 splits flexible base two ways, and reading them as one thing is where most ordering mistakes start.

Material type answers “what is this made of”. Crushed stone from a quarry and recycled crushed concrete are different types under the same item. Type A is the crushed-stone type most Texas plans name; crushed concrete is commonly supplied under Type D.
Grade answers “how tightly is it controlled”. Grade sets the gradation envelope and the Atterberg caps. Grades 1 and 2 are the tight ones, at a Plasticity Index of 10 or less and a Liquid Limit of 40 or less, which is why “Grade 1-2” shows up on so many Texas plan sheets.

A job can therefore call for recycled material at a tight grade, or virgin stone at a loose one. Type and grade are independent, and quoting one without the other is how a load shows up that nobody can accept.

The practical read: type is a yes/no gate, grade is a number. If the plans name a type your yard cannot supply, no price fixes it. If the plans name a grade, the material has to test to it, and compaction is verified in the field against maximum dry density. We source the type and grade the plans call for and send the documentation with the load.

When crushed concrete is the right call

Recycled crushed concrete earns its place on a large share of commercial site work, and on those uses the cost difference is real money at volume.

Stabilized site access and temporary haul roads. These have to carry loaded trucks over soft ground for months, not carry a finished pavement for thirty years. Recycled base does that job at a lower delivered cost.
Equipment laydown and staging yards. Same logic. The requirement is all-weather bearing, not a pavement spec.
Sub-base under a specified base course. Where the plans allow a recycled sub-base beneath the spec layer, this is usually the cheapest way to build the section.
Jobs with a recycled-content or diversion target. Crushed concrete is reclaimed material, so it counts where a project is tracking that.

When it is not

The deciding document is always the plan, not the price sheet. Crushed concrete comes off the table when:

the plans specify a crushed-stone type outright, which is common on public and roadway work;
the spec names a grade the available recycled material will not test to;
the owner or the job restricts recycled material for its own reasons.

None of those are judgements about whether crushed concrete performs. They are judgements about what the contract will accept, which is a different question and the only one that matters at delivery.

A sourcing note worth knowing before you compare quotes: base is sold by the ton and hauled by the ton, so haul distance is part of the material decision. A lower per-ton number from a yard an hour further out is not automatically the cheaper delivered number, and on a base order measured in thousands of tons that gap stops being a rounding error. Compare delivered, not at the gate.

How to order either one

Send three things and the quote is straightforward: the spec line off the plans (item, type and grade), the tonnage, and the job-site location. If you only have square footage and a depth, run it through the soil calculator first and send the volume. We supply flex base, road base and recycled crushed concrete in commercial volumes across DFW, Austin, San Antonio and Houston, and gravel carries its own separate minimum.

Flex base and crushed concrete FAQ

Is crushed concrete the same as flex base?

Not quite, and the distinction is the whole answer. Flexible base is a specification, TxDOT Item 247, and crushed concrete is one of the material types that specification allows. So crushed concrete can be supplied as flex base, but flex base does not have to be crushed concrete. Most Texas yards default to crushed stone when you order flex base without naming a type.

Is crushed concrete as strong as crushed stone base?

For a large share of base and stabilized-access uses, yes. Item 247 recognizes crushed concrete as a base material type, and it compacts into a stable, load-bearing layer. Whether you can use it on a given job is decided by the spec on the plans rather than by performance, and public and roadway work frequently calls for crushed stone.

What does Type A and Type D mean on my plans?

They are Item 247 material types. Type A is crushed stone produced from quarried aggregate, which in Texas is most often crushed limestone. Crushed concrete is commonly supplied under Type D. The type is a gate: if the plans name one your supplier cannot furnish, price does not fix it, so read the type before you compare quotes.

What is Grade 1-2 flex base?

Grade is the control level Item 247 applies on top of the material type, covering gradation and the Atterberg limits. Grades 1 and 2 are the tight ones, at a Plasticity Index of 10 or less and a Liquid Limit of 40 or less, which is why plans so often specify Grade 1-2 for base course. Grade and type are independent, so a job can call for a recycled type at a tight grade.

Which is cheaper, flex base or crushed concrete?

Recycled crushed concrete is usually the lower per-ton material. Compare delivered rather than at the gate, though, because base is hauled by the ton and haul distance can close or reverse that gap. Send the spec line, the tonnage and the site location and we price both where the plans allow both.

Need flex base or crushed concrete delivered?

We supply flexible base, road base and recycled crushed concrete in commercial volumes across DFW, Austin, San Antonio, and Houston. Send the spec line off your plans with the tonnage and the site, and we source the type and grade it calls for. See our service areas.

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