id	keyword
app01-5456	fly
app01-5456	ash
app01-5456	concrete
app01-5456	cement
app01-5456	indentation
app01-5456	doi:10.1016
app01-5456	material
app01-5456	replacement
app01-5456	phases
app01-5456	ccps
app01-5456	properties
app01-5456	aggregate
app01-5456	coal