Utilization of By-Product Materials of Building Construction and Demolition to Conserve Water and Soil in Kuwait

The recent boom in construction activities and the continued urban development in Kuwait have resulted in the generation of massive quantities of construction/demolition material by-products that need to be removed from construction/demolition sites in the cities to landfill areas which are limited in the country. This paper explores the possibility and benefits of utilizing by-product materials of construction/demolition activities for soil and water conservation. Procured concrete and asphalt and manually crushed sandstone mulch aggregates of size 5-10 mm (small size), 10-25 mm (medium size) and 25-50 mm (large size) at 25%, 50% and 75% density were used in the 28 treatments at the experimental sites at Sulaibiya. The control was devoid of any mulch. The results indicated no negative effects on soil pH, EC and heavy metal content due to the use of construction and demolition waste as soil mulch. All the units with mulch recorded higher moisture content than control. Units with asphalt 5-10 mm at 75% density, 10-25 mm at 50% and concrete 5-10 mm at 50% density recorded highest infiltration rate at the end of the experimental period. Units with asphalt mulch recorded highest microbial population and average annual, perennial and total plant population and diversity during spring and late spring. It can be concluded that utilization of construction and demolition waste can be used as mulch to conserve soil moisture, increase the infiltration rate and thus, promoting native plant growth. Among the soil aggregates, asphalt mulch enhanced germination and plant growth and was more efficient in retaining soil moisture and thus, supporting plant survival for a longer period than control.