The influence of various slag mineral concentrations to physical properties of paving block products and its characteristic

Abstract

Slag is a waste product from steel industry that has unique properties. In the presence of water, slag reacts with calcium hydroxide at ordinary temperatures to form compounds with cementations' properties. Based on this property, slag can be used as a partially cement substitution. The influence of various slag concentration to paving block physical properties and characteristic were studied in this research. Sample paving blocks casted without addition of slag and with addition of 5 %, 15 %, 25 %, and 35 % of slag are compared. Also, the grain size of slag with 60 and 80 mesh is also compared. This research shows that the greater variation in the concentration of slag minerals makes compressive strength tends to decrease, and the absorption and porosity tend to increase. The highest compressive strength test is achieved by sample of paving block with addition of 5 % slag and has 80 mesh of grain size. Hydration of cement and slag to formed calcium silicate hydrate reaction take place in the sample which cause strong bonding among all solid material. XRD characterization shows the phase formed dominated by the four phases, gismondine (CaAl2O8.4H2O), quartz (SiO2), calcite (CaCO3), and C-S-H (1.5 CaOSiO2..xH2O).