Quality Control Technician

Responsibilities Perform standardized fresh concrete tests at the plant and on jobsites, including slump (ASTM C143), air content (ASTM C231 pressure method and ASTM C173 volumetric method), unit weight/yield (ASTM C138), and concrete temperature (ASTM C1064). Fabricate and cure concrete test cylinders (ASTM C31) for compressive strength testing; ensure proper initial curing, transport, and storage procedures are followed. Sample fresh concrete per ASTM C172 sampling procedures from mixer trucks at plant and delivery points. Perform wash-out yield checks and monitor batch-to-batch consistency throughout production shifts. Record all test data accurately and completely on field worksheets and in the quality management system. Hardened Concrete Testing Prepare, cap (sulfur or neoprene pad), and test concrete cylinders for compressive strength per ASTM C39 at required ages (7-day, 28-day, and as specified). Operate and maintain the compression testing machine, ensuring calibration is current and testing procedures comply with ASTM standards. Evaluate and report compressive strength results; identify trends, flag low breaks, and initiate investigation of non-conforming results. Maintain organized specimen storage, labeling, and curing room/tank conditions (temperature and moisture per ASTM C511). Aggregate & Raw Material Testing Perform aggregate quality tests including sieve analysis/gradation (ASTM C136), moisture content (ASTM C566), specific gravity and absorption (ASTM C127/C128), and unit weight (ASTM C29). Monitor incoming raw materials (cement, fly ash, slag, silica fume, admixtures, aggregates) for conformance with approved material submittals and specifications. Collect and maintain aggregate stockpile samples; perform routine gradation checks to support mix design adjustments. Test and document batch water quality per ASTM C1602 requirements, including reclaimed/recycled water when applicable. Maintain organized records of all mill certifications, material safety data sheets, and supplier test reports. Mix Design & Documentation Support Assist the Director of Quality Control with trial batch production and evaluation for new and revised mix designs. Maintain the mix design library and ensure current approved designs are loaded in the batch plant control system. Prepare and submit concrete mix design submittals, material certifications, and test reports to engineers, inspectors, and project owners as required. Generate daily, weekly, and monthly QC reports summarizing production volumes, test results, non-conformances, and corrective actions. Support internal and external audits, including NRMCA plant certification and state/local agency inspections. Plant & Field Quality Assurance Monitor batch plant operations to verify proper material proportioning, batching tolerances, and mix time compliance. Calibrate and verify plant scales, moisture probes, and metering equipment on scheduled intervals. Coordinate with drivers and dispatch to address quality concerns at the point of delivery, including slump adjustments, water additions, and load rejections. Investigate and document customer quality complaints; participate in root cause analysis and corrective action implementation. Maintain QC laboratory equipment in clean, calibrated, and working condition; schedule external calibrations as required. Requirements Associate’s degree or coursework in concrete technology, civil engineering technology, construction management, or related field. ACI Concrete Laboratory Testing Technician – Level I or Level II certification. NRMCA Concrete Technologist certification. Experience with Command Alkon COMMANDbatch or similar batch plant control systems. Experience with mix design development per ACI 211.1 methodology. Idaho Transportation Department (ITD) certified materials tester or familiarity with ITD concrete specifications. Bilingual English/Spanish a plus. Physical Requirements Ability to lift and carry up to 60 lbs regularly (concrete cylinders, aggregate samples, testing equipment) and up to 80 lbs occasionally. Ability to stand, walk, bend, kneel, and squat for extended periods in laboratory and field environments. Manual dexterity for operating precision testing equipment and handling small tools. Work performed in laboratory, plant yard, and outdoor jobsite settings; exposure to concrete dust, chemical admixtures, noise, and varying weather conditions including cold Idaho winters and warm summers. Ability to safely navigate active construction sites, batch plant facilities, and aggregate stockpile areas. Work Schedule & Conditions Standard schedule: Monday–Friday, start times typically 4:00 AM–6:00 AM to align with batch plant production schedules. Overtime and occasional Saturday work required during peak construction season (typically April–November in the Boise market). Must be available for early-morning and occasional after-hours cylinder breaks and testing as project schedules demand. Local travel to jobsites and project locations throughout the Boise/Treasure Valley area. Summary The Quality Control Technician is responsible for testing, monitoring, and documenting the quality of ready-mix concrete products produced and delivered by Sunmat Materials at the Boise, Idaho facility. This position ensures all concrete mixtures meet project specifications, company standards, and applicable ASTM, ACI, and NRMCA requirements through rigorous sampling, testing, and reporting procedures. The QC Technician works closely with batch plant operators, drivers, and project teams to maintain consistent product quality and support continuous improvement initiatives. #J-18808-Ljbffr Kids for the Future