SETTING TIME DATA

Handout Tests on Cement Paste Determination of Setting Time of Cement

What is the setting and setting time?

The term "setting" it used in describe the stiffening of the cement paste. The length of time starting from mixing of the cement and water until the cement paste sets is called "setting Fime

#Why witting time" is important?

Setting time of the cement is important, because the cement paste is shapeable only during this time Initial setting time and final setting time cannot exceed values which is determined in standards. If initial setting time exceeds values determined in standard, it may set during pouring

How it is measured?

a$)$ Prepare a cement paste in normal consistency. We can prepare cement paste according to water proportion or consistency. But we will prepare cement paste according to consistency because it is useful in terms of practical application. Normal consistency is determined for provide consensus on theconsistency of cement paste through some standards. Determination of Normal Consistency Method is used for determining whether cement past is in accordance with normal consistency or not. $0\mathrm{.}28$ water$-$ cement ratio is used to obtain a cement paste in normal consistency.

b$)$ Measure the $450$ g cement and $126$ ml$.$ water and put them all in the laboratory mixer and watit $30$ s for absorption$.$

c$)$ Run the mixer at low speed for $30$ s$.$

d$)$ Stop the mixer for $15$ s then let the cement paste rest.

e$)$ After that, run the mixer at high speed for $60$ s$.$

f$)$ Place the fresh cement paste into vicat ring.

g$)$ Put the vicat ring at the automatic vicat device $($vicatronic$).$

h$)$ Wait for $30$ min in room condition.

i$)25$mm penetration value $($between end of needle and bottom plate$)$ corresponds to initial setting time.

j$)$ No penetration $($between end of needle and top of the ring$)$ corresponds to final setting time.

#Prepare a lab report according to following criteria

a$)$ Introduction

b$)$ Experimental

Meterials

Apparatus

Methods$/$Procedures

c$)$ Results$/$Discussions

d$)$ Conclusion

Evaluate the results comparing to standard limitation in terms of conformance.