Influence of Waste Marble Dust on the Improvement of Expansive Clay Soils

Table 3

Chemical composition of MD, raw soil, and raw soil-MD mixes, as determined from XRF.

Symbol	MD	MD0	MD5	MD10	MD15	MD20	MD25
SiO2	3.96	49.47	48.3	45.9	44	42	39
AL2O3	0.51	12.85	12.5	12.3	11	10.8	10.3
Fe2O3	1.19	11.94	7.6	8.4	8.6	8.4	9
CaO	72.26	5.79	8.2	8.8	9.1	9.6	11
MgO	0.27	2.1	2.6	2.1	1.6	2.9	2.6
K2O	0.08	1.61	1.2	1.3	1.2	1.3	1.3
TiO2	—	2.98	2.4	1.6	2.7	1.8	2.6
SrO	—	—	2.1	2.4	2.7	2.2	2
SO3	0.17	4.29	4.2	3.5	3.8	3.3	3.1
MnO	—	0.33	0.3	0.3	0.22	0.28	0.3
LOI	21.56	8.64	10.6	13.4	15.08	17.42	18.8