ACI CQTM case studies
ACI CQTM · Put your knowledge to work in context.
The Concrete Quality Technical Manager (CQTM) credential is one of the certification programs offered by the American Concrete Institute (ACI). ACI describes its certification offerings as designed to form a minimum qualification for personnel employed within the concrete construction industry, and it groups the CQTM program under Construction / Specialist Programs, which ACI says assess the knowledge of concrete construction practices in various specialty applications. The ACI CQTM case studies are 5 cases and about 2,547 words.
1Slump Test Disagreement on a Pumped Placement
A ready-mix supplier delivers 8 m³ of a C30/37 mix with a specified slump class of S3 (100–150 mm) to a residential slab pour. The site engineer performs a slump test on the first truck and records 165 mm, which is outside the specified class.
581 words, about 3 min2Low Cube Results on a Column Lift
A 28-day cube test report for a column lift of C35/45 concrete shows three cubes from one sample at 33.0, 34.5 and 36.0 MPa. The specification requires characteristic strength of 35 MPa with conformity assessed on groups of results.
544 words, about 3 min3Plastic Cracking on a Windy Slab Pour
A large external slab (approximately 400 m²) is being placed on a warm, breezy day: air temperature 28 °C, wind speed around 25 km/h, relative humidity 35%. The concrete is a C25/30 mix with a slump of 120 mm and no fibres.
471 words, about 2 min4Non-Conforming Aggregate Moisture and Batch Adjustment
A concrete plant is producing a C30/37 mix. The approved mix design assumes a sand moisture content of 5.0%.
475 words, about 2 min5Curing Compound Omission on a Structural Wall
A 300 mm thick reinforced concrete retaining wall (C35/45, exposure class indicating a need for curing) is cast in warm weather. The specification requires curing compound to be applied to all formed surfaces as soon as practicable after striking.
476 words, about 2 min