InstaBidsTypes of concrete?
Types of concrete describe overlapping attributes: ready mixed names delivery, reinforced concrete combines steel and concrete, and pervious concrete provides drainage through connected voids. ACA gives a 3,000 psi example at 28 days and describes high-strength concrete as typically 8,000 psi or greater; ACI reports pervious voids of 15 to 35%. Choose by structural purpose and drainage needs. (source: American Cement Association)
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Concrete types describe different parts of the specification
| Options | What the label means | What to distinguish in a bid |
|---|---|---|
| Ready mixed / cast-in-place concrete | Batched at a plant and delivered for placement at the jobsite. | Specify the mixture and testing age; 3,000 psi at 28 days is ACA’s example, not a universal project requirement. |
| Reinforced concrete | Steel provides tensile strength; concrete provides compressive strength. | Name the member and reinforcement design; a material label does not describe the complete structural system. |
| Precast concrete | Concrete is cast in a mold and cured in a controlled environment before transport to the site. | Identify the actual product and its exposure: NPCA ties service life to design, application and maintenance. |
| Prestressed concrete | High-strength steel tendons induce compression to counter tensile stresses in service. | Identify the stressing method; post-tensioning stretches the steel after the concrete hardens. |
| Structural lightweight concrete | Structural lightweight concrete reduces the dead load on a structure. | NRMCA gives 90 to 120 lb/ft3 equilibrium density and specified compressive strength greater than 2500 psi for structural applications. |
| High-strength concrete | ACA’s FAQ describes concrete with strength of 8,000 psi or greater. | Write the specified strength and measurement age; standard practice measures compressive strength at 28 days. |
| Pervious concrete | Connected voids allow water through; ACI reports void content of 15 to 35%. | Discuss drainage and acceptance testing; conventional slump and cylinder-strength acceptance does not transfer to pervious concrete. |
| Self-consolidating concrete | Highly flowable concrete fills formwork around reinforcement without mechanical consolidation. | NRMCA reports typical slump flow of 18 to 32 inches, tested under ASTM C1611. |
Service-life evidence belongs to a component and use
| Options | Published estimate or observed service |
|---|---|
| Concrete flatwork | 50 years: HUD planning estimate for multifamily flatwork, including walks, plazas, terraces and patios; not a ready-mixed recipe lifespan. |
| Reinforced slab foundation | 100 years: HUD planning estimate for the multifamily foundation row “Slab, reinforced concrete.” |
| Post-tensioned slab foundation | 100 years: HUD planning estimate for the multifamily foundation row “Slab, post tensioned.” |
| Precast tilt-up wall panel | 60 years: HUD planning estimate for the multifamily exterior-wall row “Precast Concrete Panel (tilt-up).” |
| Pervious pavement projects | 20 to 30 years: NRMCA describes projects with good to excellent performance over these service lives; not a prediction for every installation. |
Weather changes the placement plan
Cold / freeze-thaw with deicing chemicals
NRMCA warns that pervious concrete made with limestone aggregate may be more susceptible to deicing-chemical degradation; its guide discusses alternate aggregates for severe freeze-thaw exposure. Keep the aggregate and deicer exposure in the discussion.
Hot climates
NRMCA identifies hot weather, long hauls and jobsite delays as conditions that adversely affect SCC flow. Ask how the proposed placement will retain the required flow characteristics.
Dry / arid and windy climates
NRMCA says moisture may rapidly evaporate from pervious concrete in low humidity or windy conditions. A pervious proposal should describe how curing moisture will be maintained under those conditions.
What is pervious concrete?
Pervious concrete has connected pores that let water pass through the pavement. ACI reports 15 to 35% void content and general drainage rates of 2 to 18 gal./min/ft2; those ranges describe the material, rather than an infiltration result for a particular driveway.
NRMCA’s mix-design guide suggests 15 to 25 percent voids. Keep that mixture-design guidance separate from ACI’s wider report range; averaging the figures would erase their different scopes. Ask how the proposed mixture will be accepted, because conventional slump and cylinder-strength acceptance methods do not apply.
Source: PIP 4 — Guide to Pervious Concrete Mix Design, read 2026-11-09
Source: PRC-522-23 — Pervious Concrete report abstract, read 2026-11-09
Source: PIP 3 — Acceptance Testing of Pervious Concrete, read 2026-11-09
What is reinforced concrete?
Reinforced concrete combines steel’s tensile strength with concrete’s compressive strength. HUD’s undated CNA table assigns 100 years to the multifamily foundation row “Slab, reinforced concrete”; that planning estimate concerns that component, not every reinforced beam, wall or patio.
Separate ordinary reinforcement from prestressing when reading a proposal. Prestressed members use high-strength steel tendons to induce compression that counteracts tensile stresses in service; post-tensioning stretches steel after the concrete hardens. State the actual structural system in the scope.
Source: Applications of Cement, read 2026-11-09
Source: CNA e-Tool Estimated Useful Life Table, read 2026-11-09
What is lightweight concrete?
Structural lightweight concrete reduces structural dead load. NRMCA’s current linked CIP 36 gives an equilibrium density of 90 to 120 lb/ft3 and specified compressive strength greater than 2500 psi for structural applications. Specify equilibrium density under ASTM C567 rather than treating all lightweight fills as structural concrete.
Source: CIP 36 — Structural Lightweight Concrete, read 2026-11-09
What is high strength concrete?
High-strength concrete typically means strength of 8,000 psi or greater in ACA’s FAQ. The specified strength and its testing age belong together: ACA describes standard compressive-strength measurement at 28 days. A high-strength label does not by itself describe drainage, reinforcement or the finished component.
Source: Cement & Concrete FAQ, read 2026-11-09
What concrete made of?
Concrete combines aggregates, cement and water, with supplementary cementitious materials, fibers or chemical admixtures included in some mixtures. ACA says aggregates occupy 60% to 75% of concrete’s total volume. Ready mixed describes plant batching and delivery, so that label alone does not identify a reinforcement system.
Source: Applications of Cement, read 2026-11-09
Put the mixture and structural system in writing
- Name the component being built and distinguish site-cast delivery from precast manufacture.
- List specified compressive strength and the age at which it will be measured.
- Identify reinforcement and any prestressing method, including whether steel is tensioned after hardening.
- For structural lightweight concrete, state the equilibrium density and its ASTM C567 basis.
- For SCC, state the required slump-flow range and ASTM C1611 test method.
- For pervious pavement, describe drainage acceptance separately from conventional cylinder-strength acceptance.
- Address pervious aggregate choice for freeze-thaw and deicer exposure.
- Describe the curing-moisture plan for pervious placement in low humidity or wind.
Sources
- Applications of Cement — American Cement Association; undated; read 2026-11-09.
- Cement & Concrete FAQ — American Cement Association; undated; read 2026-11-09.
- CIP 36 — Structural Lightweight Concrete — National Ready Mixed Concrete Association; undated linked revision; read 2026-11-09.
- CIP 37 — Self-Consolidating Concrete — National Ready Mixed Concrete Association; undated linked revision; read 2026-11-09.
- PIP 4 — Guide to Pervious Concrete Mix Design — National Ready Mixed Concrete Association; undated; read 2026-11-09.
- PIP 1 — Guide to Specifying Pervious Concrete — National Ready Mixed Concrete Association; undated; historical standard references; read 2026-11-09.
- PRC-522-23 — Pervious Concrete report abstract — American Concrete Institute; 2023; read 2026-11-09.
- CNA e-Tool Estimated Useful Life Table — HUD; undated; multifamily planning estimates; read 2026-11-09.
- Pervious Pavement: Structural Design Considerations — National Ready Mixed Concrete Association; undated; observed service history; read 2026-11-09.
- This Is Precast — National Precast Concrete Association; undated; read 2026-11-09.
- PIP 3 — Acceptance Testing of Pervious Concrete — National Ready Mixed Concrete Association; undated; historical standard references; read 2026-11-09.
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