Page 15 - ICJ Jan 2026

TECHNICAL PAPER

(a) Unsegregated sample (b) Segregated sample (c) Comparison between the degree of segregation and compaction
Figure 15: Effect of vibration on the segregation of lightweight aggregates

Segregation control for lightweight aggregates: During To understand the mechanism of compaction, pervious
vibration, lightweight aggregates segregate to the top surface, concrete was cast using different techniques. The samples were
resulting in a heterogeneous mix (Figure 15b). An expanded tested for paste segregation and void distributions. Results
polystyrene (EPS) based lightweight coarse aggregate was used show that on placement inside the mould, pervious concrete
to prepare different mix designs and subjected to a simulated forms large cavities due to the interlocking of aggregates
vibration-based compaction . Three different protocols were (Figure 16). Compression-based compaction fails to overcome
[34]
used to simulate vibration, representing similar maximum the interlocking (Figure 16). Although vibration achieves better
amplitude, similar compaction energy, and similar compaction compaction, it also results in paste segregation and clogging
duration . Results showed that segregation primarily depends of pores at the bottom surface. In comparison, mixed methods
[34]
on maximum amplitude and rheological properties of the like proctor-based compaction yield better compaction without
[34]
mix, rather than the duration of compaction (Figure 15c) .
Therefore, lightweight aggregates can be compacted for a long segregation. Since proctor-based compaction cannot be
duration at low amplitudes to control the risk of segregation . simulated in the field, the results of changing compaction can
[34]
affect the field performance of pervious concrete. Therefore, it
Quality control for pervious pavements: Properties of pervious is recommended to follow compression-based compaction for
concrete significantly depend on the porosity of hardened the preparation of lab-scale specimens, to ensure replicability of
concrete, which is influenced by the compaction methodology. results in the field.

Figure 16: Formation of cavities during compaction of pervious concrete

THE INDIAN CONCRETE JOURNAL | JANUARY 2026 77