Study on Hygroscopic Swelling and Dehumidification Cracking Characteristics of Expansive Soil under Acid Rain and Cyclic Drying-Wetting

Table 7

Main chemical composition and content of Baise expansive soil.

Main chemistry component	Mass percentage (%)
	Undisturbed sample	One-time cyclic drying-wetting			Four-time cyclic drying-wetting
		pH = 7	pH = 5	pH = 3	pH = 7	pH = 5	pH = 3
SiO2	46.98	51.96	52.24	53.15	53.957	54.887	55.063
Al2O3	18.04	19.89	20.01	20.64	20.89	20.509	21.173
CaO	12.69	10.27	8.96	5.74	6.155	3.836	1.831
Fe2O3	7.96	7.31	6.84	5.02	6.142	5.771	3.929
K2O	3.26	3.19	2.99	2.22	3.113	2.657	1.341