Effect of Adding Scoria as Cement Replacement on Durability-Related Properties

International Journal of Concrete Structures and Materials

Table 2 Chemical, physical and mechanical properties of plain and blended cements.

Chemical composition (%)	C1/CEMI	C2/10 %	C3/15 %	C4/20 %	C5/25 %	C6/30 %	C7/35 %	C8/SRPC
Chemical properties of plain and blended cements
SiO₂	20.69	21.59	22.35	23.25	24.00	24.33	24.61	20.72
Al₂O₃	5.09	5.20	5.68	5.73	6.55	6.80	7.39	4.33
Fe₂O₃	4.23	4.75	4.79	5.15	5.43	5.47	6.31	5.79
CaO	60.62	58.21	55.18	53.05	50.30	48.00	44.84	61.69
MgO	2.46	2.66	3.23	3.39	3.87	4.11	4.63	1.21
SO₃	2.26	2.31	2.20	2.20	2.30	2.26	2.55	2.13
Loss on ignition	1.41	1.40	1.43	1.37	1.47	1.48	1.60	2.90
Na₂O	0.60	0.71	0.83	0.94	1.07	1.16	1.31	0.21
K₂O	0.35	0.39	0.43	0.46	0.50	0.53	0.57	0.19
Cl⁻	0.023	0.021	0.022	0.019	0.018	0.019	0.019	0.022
Insoluble residue	1.03	1.58	2.09	2.51	3.48	4.08	5.33	0.36
Main compounds of clinker used in cement specimens (Based on Bogue composition)
C3S	53.36	50.55	47.74	44.94	42.13	39.32	36.51	50.16
C2S	17.76	16.82	15.89	14.95	14.02	13.08	12.15	21.58
C3A	5.78	5.47	5.17	4.86	4.56	4.26	3.95	1.69
C4AF	11.53	10.93	10.32	9.71	9.11	8.50	7.89	17.60
C3S/C2S	3.0	3.0	3.0	3.0	3.0	3.0	3.0	2.32
Physical properties of plain and blended cements
Specific gravity	3.13	3.09	3.05	3.02	2.99	2.98	2.96
Initial setting (min)	151	153	153	153	152	153	158
Final setting (min)	178	179	180	180	179	181	188
Water demand (%)	25.1	25.2	25.2	25.4	25.4	25.4	25.5
Soundness (mm)	0.6	0.7	0.8	0.8	0.9	1.1	0.9
Residue on 45 µm sieve (%)	13.6	14.3	14.8	15.2	16.1	17.0	17.9
Residue on 90 µm sieve (%)	6.4	6.2	6.4	6.5	6.7	6.9	6.8
Mechanical properties of plain and blended cement mortars
Strength of mortars at 28 days curing (MPa)	45.6	44.2	42.3	40.6	37.1	33.7	30.6