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TECHNICAL PAPER

STRENGTH CHARACTERISTICS

AND ACID RESISTANCE

OF PUMICE LIGHTWEIGHT

AGGREGATE CONCRETE:

A MICROSTRUCTURAL

PERSPECTIVE CHAITALI B. GULEDAGUDD*

KANNAM PRAVEEN

Abstract applications, offering a game-changing alternative to traditional
concrete blends.
Lightweight concrete (LWC) is a pioneering solution in the
construction sector, characterized by its unique composition and By incorporating lightweight aggregates and advanced
versatile applications. Engineered with lightweight aggregates additives, LWC achieves a remarkable reduction in dry density,
[1]
and additives, LWC achieves a significant reduction in dry making it an attractive option for various construction projects .
density, making it 23 to 87 % lighter than conventional concrete. With densities ranging from a mere 300 to 1840 kg/m³, this
Pumice stone, a volcanic rock, is often chosen as a replacement extraordinary decrease in weight results in a material that is a
for coarse aggregate due to its natural lightness and porous staggering 87 % lighter than conventional concrete, defying
nature, which can improve thermal insulation properties. This the conventional norms of construction. This phenomenal
study investigates the optimal dosage of pumice lightweight weight reduction makes LWC the go-to choice for projects
aggregate in LWC production, focusing on 28 day compressive where minimizing structural load is paramount, such as towering
strength. The results show that a 40 % pumice lightweight skyscrapers, intricate prefabricated concrete elements, sprawling
aggregate replacement level is optimal for M30 and M50 grade bridge decks and overpasses, earthquake-prone zones, and
concrete, with improved compressive strength, split tensile complex prefabricated components, where every ounce of
strength, and modulus of rupture. Durability assessment of weight savings can be a game-changer .
[2]
40 % pumice-replaced concrete under 5 % sulphuric acid,
chosen for its severity, showed acceptable strength and Choosing the right aggregates is crucial for attaining the perfect
microstructural performance. Future work can include tests like characteristics in both fresh and hardened concrete. Pumice
chloride penetration, carbonation, and freeze-thaw for broader stone, being a naturally lightweight volcanic rock, stands out
evaluation. Microstructural analysis using scanning electron as the ultimate replacement for coarse aggregate in LWC due
microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) to its extraordinary combination of lightness and impressive
[3]
and X-ray diffraction (XRD) confirm the suitability of pumice strength . Formed when molten lava undergoes an intense
aggregate as a percentage replacement for normal coarse and abrupt cooling process accompanied by a dramatic drop in
aggregate in producing structural lightweight aggregate pressure, pumice develops an extraordinarily porous structure,
[4]
concrete. giving it an exceptionally low density . When incorporated
into concrete, pumice aggregates remarkably solve several
Keywords: Compressive strength, Durability, Lightweight prevalent construction challenges, such as significantly reducing
concrete, Micro-structure, Modulus of rupture, Pumice coarse weight, drastically improving thermal insulation, and greatly
aggregate, Split tensile strength.
enhancing sound absorption. Furthermore, numerous studies
1. INTRODUCTION have overwhelmingly demonstrated that pumice concrete
retains its structural integrity exceptionally well over extended
Lightweight concrete (LWC) is revolutionizing the building periods, especially in maintaining the strength and longevity of
industry with its innovative composition and diverse embedded steel reinforcements. This makes it an extraordinarily

THE INDIAN CONCRETE JOURNAL | FEBRUARY 2026 55
* Corresponding author: Chaitali B. Guledagudd, Email: R22PCV10@reva.edu.in