Custom Concrete Mix Design in Flushing, NY: The Right Mix for Projects That Need More Than a Standard Batch

A mix design documents the exact proportions of cement, water, aggregates, and admixtures in a concrete batch and the testing that verifies those proportions achieve the specified compressive strength. For structural pours in NYC, the mix design must be approved by the engineer of record and filed with the DOB before concrete is placed. Copies are required on site and provided to the testing lab. Without an approved mix design, the pour can't proceed on a permitted structural job.

For most structural concrete in NYC, a certified mix design is required. All mix designs must be certified by the approved agency's director or the concrete producer's quality control manager, signed by an officer of the concrete production facility, approved by the registered design professional of record, and filed with the DOB before use. The concrete testing lab that performs the field acceptance testing cannot be the same lab that performed the mix design, per NYC Buildings Bulletin requirements.

For many routine structural pours at standard PSI ranges, previously accepted mix designs can be submitted. For specialty applications, higher-strength mixes, or projects where the engineer has specified parameters outside a standard range, a custom mix design developed for the specific project requirements is the appropriate approach. We can advise on what your project requires when you call.

At minimum: the required compressive strength (PSI), the intended application, any admixture requirements specified by the engineer, the aggregate size, any air entrainment requirements, and whether the mix needs to be re-excavatable (for trench backfill applications). If you have engineered drawings or a project specification sheet, bring those when you call.

Timeline depends on the mix complexity and whether DOB filing is required. For straightforward custom mixes based on established proportions, documentation can often be produced relatively quickly. For mixes requiring trial batch testing and DOB review, plan for the filing and approval process before your pour date. We'll advise on realistic timelines when you call.