Cement, SCMs, and Admixtures — Worked Examples

A laboratory request asks for both normal consistency and Vicat setting time of a hydraulic cement. Determine the correct ASTM method assignment.

A concrete mixture contains $360\text{ kg/m}^3$ of hydraulic cement. Its measured relative density is 3.10. Use water density $1000\text{ kg/m}^3$ to determine cement absolute volume.

A trial mixture requires $400\text{ kg/m}^3$ total cementitious material. The approved trial plan replaces 25% of that mass with slag cement. Determine hydraulic cement and slag-cement masses.

A trial concrete contains $380\text{ kg/m}^3$ total cementitious material. The approved trial dosage is $650\text{ mL}$ per $100\text{ kg}$ of cementitious material. Determine admixture volume for an $8.0\text{ m}^3$ batch.

A production mixture that previously retained slump for 60 minutes begins losing slump rapidly after the cement source changes. Water, aggregate source, and nominal admixture dosage are unchanged. Determine a defensible investigation sequence.

A cement certificate identifies the correct product and lot and reports compliant physical and chemical results. A concrete trial made with the cement nevertheless shows delayed setting. Decide whether the certificate alone proves the concrete system is acceptable.

A reinforced-concrete placement in cold weather needs faster early strength. A chloride-bearing accelerator and a nonchloride accelerating system are both available. Determine the material-selection logic.

A thick mat has a measured core temperature of $78^\circ\text{C}$ while the near-surface temperature is $36^\circ\text{C}$. Determine the instantaneous temperature difference and the next engineering decision.