Effect of Natural Pozzolana on Physical and Mechanical Properties of Concrete

Table 3

Optimum NP dose recorded for improvement of split tensile strength by different researchers.

W/C	Dose range (%)	Curing time (days)	Optimum strength			Type of NP	References
			Age (days)	Dose (%)	Strength (MPa)
—	0, 5, 10, 15, 20	28	28	15	2.17	Bentonite	[159]
0.40	5, 10, 15, 20, 25	7, 28, 56	7, 28, 56	15	2.8	Bentonite	[160]
—	0, 10, 20, 30, 40, 50	7, 14, 28	7, 28	10	3.4, 3.75	Kaolin	[161]
0.32	0, 5, 10, 15, 20	28	28	15	4.0	Kaolin	[39]
0.53	0, 3, 5, 10	7, 28, 60, 90	7, 28, 60, 90	10	3.4, 4.3, 4.7, 5.0	Kaolin	[162]
—	0, 10, 20, 30	1, 2, 14, 28, 90, 180	14, 28, 90, 180	10	5.56, 5.58, 6.12, 6.22	Volcanic ash	[61]
3.30	0, 5, 10, 15, 20	28, 56, 90	28, 56, 90	15	12.3, 12.6, 13.3	Bentonite	[157]
0.50	0, 10, 15, 20, 25, 30, 35	7, 28, 180	7, 28, 180	15	1.5, 2.39, 2.6	Bentonite	[146]