Physical Properties of Shale Aggregate and Characteristics of Concrete in Replacement Ratio in Daegu-Kyeongbuk Region

Abstract

Sedimentary rocks dug up in construction fields are mostly stockpiled for landfill disposal, leading to an increase in construction costs and construction inefficiency. After screening, some of the sandstone can be used as aggregate; however, most of the shale ends up as industrial waste in practice. In this study, to stabilize the demand and develop resources for alternative aggregates of concrete, the potential use of shale, which is widely distributed in the Daegu-Kyeongbuk region, as a concrete aggregate was evaluated. Red and black shale exported from a Daegu excavation site was selected for use in the experiments and evaluated by comparing with hornfels, which is widely used as a coarse aggregate and is a type of andesite and metamorphosed sedimentary rock. The physical properties of the aggregate were evaluated in accordance with the test methods of KS F 2527 "crushed concrete aggregate," and the compressive strength against the shale aggregate replacement ratio was measured. The compressive strength of the concrete after 28 days was 30.8 MPa when the black shale replaced 100% of the aggregate in the concrete and 31.1 MPa when the red shale replaced 100% of the aggregate in the concrete. Compared with the compressive strength of 37.5 MPa for concrete prepared by using plain aggregate, using shale as a substitute for the aggregate produced an average compressive strength that was 82% of normal concrete.

Strength and Durability Characteristics of Cement Composites with Recycled Water and Blast Furnace Slag Aggregate

“…Meanwhile, studies on alternative aggregate resources were conducted owing to the recent shortage of natural aggregates for concrete [ 10 , 11 ], and some studies on using blast furnace slag, a byproduct of the steel industry, as aggregates for concrete were reported [ 12 , 13 , 14 , 15 ].…”