From this experiment I conclude that the cement can hold very high compressive stresses but it can’t when it comes to tensile stresses. Also in Figure 1 above the curves should not be like that they somehow must be like square root of x figure of course not exactly but similar to it and that is due to the huge error that had happened.
I also conclude that the strength of the cement reaches its maximum at 28 days and it keeps increasing but not in the same rate it was increasing in the first 28 days. It is considered to be small compared with rate in the first 28 days.
The major source of error in this experiment was the performer of it, for example they filled the molds with mortar but the tamping was so bad that they didn’t let the tamping rod fall freely under its own weight as written in the ASTM.