Three standard mortar cubes were made using questionable water available at job site and three others were made using potable water. The table shows the $7-$day compressive strength $($in pounds$)$ of the cubes. Also, the Vicat test showed that the set time of cement paste made with questionable water was $1$ hour more than the set time of paste made with potable water. Based on these results, is the water acceptable for mixing concrete per ASTM standards? $12$ points

$\backslash$table$[[$Questionable water,Potable water$],[16,100,15,690],[15,820,16,820],[15,380,16,720]]$

compressive strength

$=\frac{15,690+16,820+16,720}{3}$

$=16,{410}^k$

kips

$=16,40$ kips

$90\%$ compressive $=0\mathrm{.}9(16,410)={14769}^2$

strength

strength

$??$ Set time?