Use of Plant-Based Accelerator to Enhance Rate of Gain of Strength of Kenyan Blended Cement ()
ABSTRACT
Concrete is the most widely used construction
material in the world. The situation in the country is not an exception as most
of the infrastructures in Kenya such as
buildings, bridges, concrete drainage among others, are constructed using
concrete. Sadly, the failure of buildings and other concrete structures is very common in Kenya. Blended Portland
cement type 32.5 N/mm2 is the most widely used concrete binder material and is
found in all parts of the country. Despite blended cement CEM 32.5 being the
most commonly used cement type in construction industry in Kenya and most developing
countries as a result of its low price and availability locally, its strength
gain has been proven to be lower compared to when other types of cement are
used due to quantity of pozzolanic material added to the blend. This paper
outlines findings of an experimental investigation on the use of cypress tree
extract as an accelerator to enhance rate of gain of strength on Kenyan blended
cements. Six different blended cement brands locally available were used during
the study. Cement chemical analysis was done using X-ray diffraction method
while for the cypress extract, Atomic Absorption Spectrometer machine was used.
Physical and mechanical properties were checked based on the British standards.
The generation of the concrete mix design was done using the British DOE method
and concrete was tested for the compressive strength at 7, 14, 21, 28, 56 and
90 days. It was observed that 15% dosage of the extract expressed as a mass
percentage of the cement content gives the most improved compressive strength
of concrete, 10.4% at 7 days and 9.5% at 28 days hence the optimum. It was
further noted that when Cypress tree extract is used as an accelerator in the
mix, the blended cement concrete achieves the design strength at 27 days saving
10 days of the project duration compared to when no accelerator is used while
the ultimate strength is achieved at 67 days. The study therefore recommends
the use of the cypress tree bark extract at a dosage of 15%, by mass, of the
cement content as an accelerator when the structure is to be loaded at 28 days
and waiting up to 39 days before loading the structure if no accelerator is used for blended
cement concrete.
Share and Cite:
Onjure, E. , Kabubo, C. and Okumu, V. (2023) Use of Plant-Based Accelerator to Enhance Rate of Gain of Strength of Kenyan Blended Cement.
Open Journal of Civil Engineering,
13, 399-410. doi:
10.4236/ojce.2023.133030.
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