And Answers 2024/2025
/. Concrete is a mixture of _____, ______, and ______. - Answer-cement, water, and
aggregates.
/.The most commonly used concrete for structural purposes is: - Answer-Normal weight
concrete.
/.Normal weight concrete weighs approximately: - Answer-140 lb/ft^3
/.Lightweight structural concrete may weigh from _____ to ______ lb/ft^3. - Answer-90,
100
/.Heavyweight concrete may weigh ______. - Answer-200 lb/ft^3 or more.
/.Most concrete today is made with: - Answer-Portland Cement
/.Concrete is usually referred to as a mixture of two components; ______ and _______.
- Answer-aggregate, paste
/.The hardening process of the paste is a chemical reaction called _________. -
Answer-Hydration
/._______ is developed in the hydration process. It may peak up to _______ degrees. -
Answer-heat;130 F
/.Concrete does hardens and cures by drying. True or False - Answer-False ; Concrete
does not harden or cure by drying, because cement needs moisture to hydrate and gain
strength. When concrete dries fully, hydration stops, and it no longer gains strength.
/.A mixture of cement and water is called: - Answer-paste
/.When sand is added to paste it is called: - Answer-mortar or grout
/.When coarse aggregate is added to mortar, the combination is called ______. -
Answer-concrete
/.________ make up about 60 to 75% of the volume of concrete - Answer-Aggregates
/.The particle size distribution or combined coarse and fine aggregate gradation should
have all sizes present in adequate amounts. True or False - Answer-True. If the
gradation is evenly distributed adequately the void content to be filled by the cement