Page 10 - ICJ Jan 2026

TECHNICAL PAPER

across different dosages, excess water, particle sizes, animal fall probability. Further investigation in this direction is needed
dung, processing techniques, freshness of dung, and age of the to evaluate walking comfort with the reduced elasticity or to
prepared powder. The consistency of results across repeated engineer pavement with similar elasticity.
testing helped demonstrate the application of cow dung as a
foaming agent. 3.3.4 Fine bone china ceramic aggregates

Limitations: Due to high moisture content, the foaming Fine bone china is a high-strength ceramic with high Ca
[20]
3
agent failed to demonstrate densities below 1200 kg/m or (>20 %) content . In general, powdered wastes with high Ca
compatibility with steam curing. Furthermore, the developed content show a good pozzolanic reactivity. However, fine bone
foaming also alters the strength development in the prepared china is one observed exception where the waste performs
mixes, limiting the scope of its application. At higher dosages, better as an aggregate than SCM. As an SCM, fine bone china
early age strength development is delayed. While it is ceramic powder can be used as a 20 % substitute for cement.

speculated to be a result of Ca distribution due to a higher At higher dosage, the high volume of P 2 O 5 (>10 %) starts
2+
effective w/c ratio, the specific mechanism is under further affecting the pozzolanic activity. As a fine aggregate, fine bone
investigation. Due to lower early age strength, for mortars with china can replace up to 60 % of natural sand without showing
[20]
3
a density below 1600 kg/m demoulding period increased from any detrimental effect on the properties of concrete . The
16 h to up to 40 h. Cow dung has shown an additional property fine bone china aggregate supports nucleation, or C-S-H gel
of internal curing with up to 90 % strength in the absence of deposition, around the ITZ and improves the microstructure of
[21]
external curing, as opposed to 60 % strength in control samples. concrete, as shown in Figure 7 .
Further investigations are needed to optimise the application of The resulting concrete shows better strength (compressive,
cow dung as an internal curing agent.
flexural, split tensile), residual performance after fire exposure,
3.3.3 Waste tyre rubber and its specialised impact resistance, sulphate resistance, chloride resistance,
[20,22–27]
application abrasion resistance and acid resistance . Although
the strength improvement can be observed up to 100 %
Waste tyre rubber has been upcycled in concrete in the form replacement, more than 60 % is not recommended due to
[20]
[14]
of crumbs, chips, powder and fibres . The addition of tyre reduced workability . Overall, the fine bone china ceramic
rubber is typically detrimental to the compressive strength of aggregate can be used as a partial substitute for sand to
[11]
the concrete and not recommended for most applications . develop high-performance concrete.
Interestingly, the addition of waste tyre rubber in fibre form Key contributions: Extensive investigations were conducted
improves the flexural strength, energy absorption capacity to demonstrate the suitability of fine bone china ceramic
and surface friction of concrete, suitable for pavement
applications [15-18] . For different compositions of rubber fibre- aggregates as a sustainable replacement for natural river sand.
added concrete, as compared to control, energy absorption While new scientific insights were not observed, the studies
can be increased by up to 30 % in terms of drop impact, validated the role of Ca towards nucleation and microstructural
energy absorbed till the first crack can be increased by up to improvement.
five times, and abrasive wear can be reduced by about 45 %, Limitations: The observed improvements in the microstructure
implying better material durability [15-18] . Furthermore, the friction are attributed to the presence of higher Ca content, based
coefficient can be increased by 0.15, resulting in reduced slip on an extensive literature review. No suitable experiment
and fall probability. At the same time, energy absorbed results was identified to validate whether any other factor played a
in reduced rebound energy, which can reduce the fall-related contributing role towards the microstructural improvement.
injuries . The improvement in energy absorption and abrasive
[18]
resistance can also be observed for rubberised ash, obtained
after pyrolysis of tyre rubber . However, the efficacy of rubber 4. RHEOLOGY
[19]
ash is lower than the fibres [18,19] . The understanding of the rheology of cement composites
is derived from observations on non-hydrating colloids and
Key contributions: Extensive investigations were conducted
to identify viable applications for waste tyre rubber. While suspensions. The hydration of cement affected properties
some of the scientific insights have been previously reported, over time, making it difficult to separate the effect of different
[28]
studies related to friction and the proposed anti-slip pavement factors on the rheological properties at a given point in time .
applications are novel. Often, the rheology of cement was reported as a contradictory
[28]
phenomenon across different studies . This limited a
Limitations: The use of rubber also reduces the elasticity of the generalised understanding of rheology and its application for
concrete, which can affect walking comfort and increase the advanced applications like 3D printing. The gap in fundamental

72 THE INDIAN CONCRETE JOURNAL | JANUARY 2026