Inhaltszusammenfassung

Sufficient green strength of refractory castables is necessary to avoid failures during demoulding of refractory linings. However, there is a lack of knowledge on the mechanisms of the formation of grenn strength of refractory castables. This work focuses on effects within the matrix of PCE-dispersed and CA-cement-bonded refarctory castables during their setting that contribute to their green strength. The mechanisms of formation of green strength of CA-cement-bonded refractory castables are ...Sufficient green strength of refractory castables is necessary to avoid failures during demoulding of refractory linings. However, there is a lack of knowledge on the mechanisms of the formation of grenn strength of refractory castables. This work focuses on effects within the matrix of PCE-dispersed and CA-cement-bonded refarctory castables during their setting that contribute to their green strength. The mechanisms of formation of green strength of CA-cement-bonded refractory castables are strongly related to the amount of pore water which is present in the matrix (lubricating film between particles). If pore water is reduced, green strength increases due to additional interparticle connections. Viewing sonic velocity and the amount of hydrate bond water separately does not provide sufficient information about the progress of the formation of green strength, because a first increase of sonic velocity may be correlated to a coagulation of the matrix suspension of a refractory castable without increasing the grenn strength (this is only an apparent green strength). This happens when PCE (Polycarboxylate Ether) with short side chains precipitate as Ca-PCE. Furthermore, the formation of hydrate phases does not necessarily correlate to an increase of green sterngth as well, because hydrate phases can be integrated to the rheological system up to a certain extent, suppressing the formation of interparticle connections for a while. This effect can be achieved by the use of PCE with longer side chains.» weiterlesen» einklappen

Autoren

Klassifikation

DFG Fachgebiet:
Materialwissenschaft

DDC Sachgruppe:
Ingenieurwissenschaften