Effects of lime water-saturated pumice aggregate for internal curing on the physical and mechanical properties of concrete/ Mel Patricia M. Cabrera, Kenneth Luis T. Dandal, Jhon Oliver A. De Jose, Romelito T. Dela Cruz, Fumie E. Komori, and Mierell Louise V. Ramos.--

Bachelor's Thesis

College of Engineering.-- Bachelor of science in civil engineering: Technological University of the Philippines, 2023.

Includes bibliographic references and index.

In the concrete industry, external curing with the addition of lime is the most
common method to develop concrete properties and prevent calcium carbonate from
leaching out of the concrete. However, external water could not penetrate through the
hardened concrete, leading to premature hydration which is essential to the strength
development of concrete. To maintain satisfactory temperature and moisture condition,
internal curing is an advanced method to provide internal water reservoirs in a concrete
mixture that prolongs cement hydration. The researchers aim to investigate the effects on
the physical and mechanical properties of concrete using lime water-saturated pumice for
internal curing. This study aims to determine the implications of using different
concentrations of lime water for internal curing on the properties of concrete and to
compare it to the conventional method of internal curing using clean water. This study
adapted the ACI 211.1-91 (Standard Practice for Selecting Proportions for Normal,
Heavyweight, and Mass Concrete) to generate three different concrete mix designs and
then manipulated using the Bentz and Snyder Equation to calculate the amount of water
and fine pumice aggregate for internal curing to create five mix designs with varying lime
water concentrations (0%, 20%, 40%, 50%, and 60%). The parameters studied in this
experiment are compressive strength with 162 cylindrical samples (100mm dia. by
200mm) based on ASTM C39-M, split-tensile strength with 162 cylindrical samples
(100mm dia. by 200mm) based on ASTM C496, and flexural strength with 162 prismatic
samples (150mm by 150mm by 500mm) based on ASTM C293 for the mechanical
properties of concrete. In addition, concrete density and workability of the concrete were
also analyzed using the ASTM C138 and ASTM C143, respectively. Concrete samples

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were tested on the 7th, 14th, and 28th day using the Universal Testing Machine. The results
showed slight improvement in the unit weight and workability of concrete. However, there
is a significant difference in the mechanical properties of concrete wherein compressive,
split-tensile, and flexural strength of internally cured concrete is higher compared to the
control sample as the age of concrete progresses. The concrete in terms of its compressive
and split tensile strength has similar behavior where strength increases as lime water is
introduced using internal curing reaching its peak strength at 50% limewater concentration
but slightly decreases as it approaches 60% lime water concentration. While the flexural
strength of concrete with lime water internal curing is lower than the normal concrete due
to the addition of fine pumice. However, the compressive strength increases as the
limewater concentration also increases.