Some projects need concrete that goes beyond standard ready mix: high-strength for engineered structural elements, fiber-reinforced for crack control without rebar, rapid-set for projects that have to return to service same-day, or custom mix designs to specific engineering specs. Boston Concrete supplies the specialty mix and dispatch your project requires. Every order starts with a free written quote.
Specialty mix designs serve specific engineering goals that standard ready mix cannot meet. High-strength mixes go well above standard compressive strength, sometimes for structural elements like columns or precast pieces. Fiber-reinforced mixes embed steel or synthetic fibers in the matrix for crack-control alternatives to traditional rebar. Rapid-set mixes cure to service strength dramatically faster, useful for road repair or operations that cannot afford long downtime. Custom mix designs blend admixtures to specific engineering specs for environments standard mix cannot handle.
We supply specialty mixes when the project engineer specifies them, with full mix design documentation and batch records that support structural or compliance audit. Most projects do not need specialty mix; for the ones that do, the spec is non-negotiable and getting it right matters.
We confirm the mix design from the project engineer (strength, slump, air content, admixtures, fibers, set time), with the cure target and any documentation requirements the project needs.
Design and batch
The mix is designed to the engineered spec, batched at the plant with calibration-verified proportions, and batch records are created for the documentation trail required by structural or compliance audit.
Deliver with documentation
Trucks deliver to the pour site with the batch records, mix design, and any required test cylinders for laboratory verification. Discharge happens to the placement crew or pump as agreed.
Document for audit
Mix design, batch records, delivery times, and any test results are compiled into a documentation package that supports the project's structural or compliance audit.
Why specialty matters
Spec Match Is Non-Negotiable
Specialty mix design is specified for a reason. Substituting standard mix for high-strength fails the engineered design; substituting rapid-set when standard is specified can cause cracking from too-fast hydration. The spec is the spec, and we supply to it without substitution.
Coordinate with our concrete pumping services for projects requiring both specialty mix and pumping, and with the broader industrial concrete work where specialty pours fit into larger projects.
High-strength, fibers, rapid-set, custom mixes and documentation.
Concrete with compressive strength well above standard ranges, typically for structural columns, precast elements, or engineered applications. The engineer's spec defines the strength target; the mix design is built to hit it with appropriate testing.
Crack control through synthetic or steel fibers distributed in the matrix, sometimes replacing or supplementing traditional rebar for thin slabs, overlays, and decorative pours. The fiber type and dosage match the engineered spec.
When the pour has to return to service much faster than standard concrete allows, road repair under traffic, runway repair, industrial floors with short shutdown windows. Rapid-set chemistry is different; the mix design accounts for that.
Yes, when the project requires laboratory verification. Test cylinders are cast at the pour, cured per spec, and delivered to the specified testing lab for compressive strength verification at the schedule the engineer requires.
Mix design, batch records, delivery times, test cylinder logs where applicable. The package supports structural audit and compliance review; it is part of the project deliverable, not an extra.
High-strength mix for a residential pool deck structural slab. Spec'd, supplied, documented with test cylinders. Cylinder breaks confirmed strength. Real structural ready mix.
Z. R5
Structural Engineer, Boston
★★★★★
Fiber-reinforced mix for a thin-slab overlay where rebar would have been unfeasible. Crack control through the fibers has held perfectly two years in. The engineering match was exact.
Y. R5
GC, Cambridge
★★★★★
Rapid-set mix for a floor repair during a planned 24-hour shutdown. Concrete reached service strength in time for the production restart. Saved real operating cost.
Q. R5
Industrial Operations, Somerville
★★★★★
Custom mix design for a chemically-resistant slab. They worked with our spec rather than substituting closest standard. Documentation supported the final engineering signoff.
X. R5
Engineer Consultant, Quincy
From the blog
Concrete Guides & Articles
Practical reading on planning, finishes and caring for concrete in Boston.
