W	water
MA	mineral admixture
CA	coarse aggregate
CH	curing humidity
AEA	air-entraining agent
NFTC	number of freeze–thaw cycles
LSTM	Long Short-Term Memory
SVM	Support Vector Machine
C	cement
FA	fine aggregate
CT	conservation temperature
MD	maintenance days
A	admixture
ELM	Extreme Learning Machine
RBFNN	Radial Basis Neural Networks
SSA-ELM	Sparrow Algorithm Optimized Extreme Learning Machine