9.1 LH is a term which refers to a type of cement. LH stands for Low Heat Cement
ID: 1765701 • Letter: 9
Question
9.1 LH is a term which refers to a type of cement. LH stands for Low Heat Cement. Circle all of the correct statements regarding LH cement. a) Concrete made with LH cement is suitable for use in situations where there are low ambient temperatures (eg: colder climates, early morning pours etc b) c) LH cement is suitable for use in thick concrete elements Concrete made with LH cement requires less water to achieve a particular level of workability than concrete made with GP cement d) e) Concrete made with LH cement produces less heat of hydration Strength achieved at 7 days by concrete using LH cement is lower than the strength achieved at 7 days when using GP cement f) Strength achieved at 7 days by concrete using LH cement is higher than the strength achieved at 7 days when using GP cement 9.2 Circle all of the items that will increase the hardened state strength of concrete elements. a) Having a high free water content in the concrete mix b) Having a low free water content in the concrete mix c) Designing the concrete mix with a high water/cement ratio d) Designing the concrete mix with a low water/cement ratio e Vibrating until all of the bubbles have finished coming to the surface f) Repeated wetting and drying of concrete during the first few days after the g) h) concrete has been cast Preventing the surface of the concrete from drying out Having a range of different aggregate sizes in the mixExplanation / Answer
Low Heat Cement has low heat of hydration so it produce less amount of heat evolved during setting.
No, we cannot use Low Heat Cement in cold weather conditions because it will slow the setting time than in ordinary weather.
Due to its Low heat of hydration, LH. is suiable to apply in making mass concrete.
Yes Low Heat Cement has Increased workability.So it require less water to achieve particular level of workability.
Yes,Low Heat Cement has low heat of hydration.This is due to low percentage of tri-calcium aluminate C3A and high percentage of di-calcium silicate C2S present in Low Heat cement.
The 7 day strenght of Low Heat Cement is lower than GP cement since the low heat cemet has lesser initial strength but it has high late strength
9.2
High free water content will speed up the rate of hydration hence will result in increased strength.
Concrete mix with low water/cement ratio is of high strength.
Vibration will result in better compaction,and proper compaction result in high strength of the the element.
Curing is done to maintain the optimum moisture level which helps in strengthning the concrete element,as this moisture helps in proper dissipation of heat evolved during hydration.So it is recommended to repeatedly wet the surface.
Having a range of aggregate sizes in the mix ensures that there is high degree of packing and hence lesser voids and thus higher strength.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.