Page 172 - New Trends in Eco efficient and Recycled Concrete

144 New Trends in Eco-efficient and Recycled Concrete

Figure 5.11 SSA cement pastes (0% 60% replacement): (A) cumulative curve for pore size
distribution, and (B) relationship between porosity and mechanical properties (Pavlı ´k et al.,
2016). SSA, Sewage sludge ash.

In contrast, Chen and Poon (2017a) found a good reactivity of SSA and ground
SSA in early-stage cured mortars, and that it was superior to that for FA. They
assumed that several factors affected the behaviour: (1) the absorption of water in
SSA particles, which reduced the effective w/c ratio; (2) the slow release of water
from SSA particles, which allowed them to complete the hydration of the cement
particles; and (3) the angular shape of SSA particles, which caused an interlocked
structure among the gelatinous and unreacted particles.