Equation set for ASR Modeling
R[siloxane] = -k1.[siloxane].[H2O]
R[silanols] = 2.k1.[siloxane].H2O – k2.[silaxols].[ROH]
R[ROH] = -k2.[silanols].[ROH]
R[H2O] = -k1.[siloxane].[H2O] + k2.[silanols].[ROH] – k3.[silanols].[ H2O]
R[AS gel] = k2.[siloxane].[ROH] - k3.[silanols].[ H2O]
R[expanded products] = k3.[silanols].[ H2O]
Qm = R[H2O] * 18 g/mol (8)
To solve the governing equation set, a mesoscale geometry of concrete block can be considered. For finite element analysis, a concrete geometry was created in the virtual cement concrete testing lab following the volume fraction of cement paste and aggregate particles.
For chemical reaction alkali-silicate gel is generated first around the rim of reactive aggregates and all voids are filled up with alkali-silicate gel that will expand by absorbing water.
