Material science engineering question (e) The diagram below (Figure 1) shows the
ID: 1732732 • Letter: M
Question
Material science engineering question
(e) The diagram below (Figure 1) shows the compositions of some of the cement types specified in the European Standard EN 197-1. Use this diagram to aid in answering the following questions la CEM III/C CEM IVBA 80 CEM I/A 50 CEM II/B-S VIB CEM CEM II/A-S CEM I Cement CEM IWA-M (S-V Fly ash CEM II/A-V CEM II/B-V Figure 1 i. Which is likely to have the higher embodied energy: CEM I or CEM V/B? ii. Which is likely to have higher early strength: CEM IIB-S or CEM IIB-V? iii. Which has a higher overall Ca/Si ratio: CEMI or CEM IIIB? iv. Which will have the higher ratio of 90-day strength to 7-day strength: CEM V/B or CEM IIA-S? Which would be expected to have higher resistance to sulphate attack: CEM I or CEM III/C? v. vi. Why is CEM V/B classified as a ternary blended cement? [6 marks] (f) You are constructing a building, using a concrete mix which has been specified and tested in the laboratory to have a 28-day strength of 40 MPa. However, the contractor who is placing the concrete decides to add more water into the mixer truck before placement. List four ways in which this will change the properties of the hardened concrete 4 marks]Explanation / Answer
e) (i) Cem I has higher embodied energy since more fly ash content means less embodied energy.
(ii) Cem-II B(V), Higher fly ash content, higher is the early strength.
(iii) Cem-I since it has more cementiotious content hence, Ca than slag.
(iv) Cem- V(b)
(v) Cem - I since it has more cmeentitious content.
(vi) Cem V(b) comprises of all three blends of the mix in a good proportion i.e. cement, flyash and slag. Hence, it is called ternary blended cement.
f) a) Long term Strength of the concrete will be lesser than expected.
b) Slump of the working mix shall be higher.
c) Early strength of the mix shall be achieved early due to higher water content.
d) Requirement of curing after concreting shall be lesser.