Evaluation of the performance of sugarcane molasses as a plasticizer admixture in cement mortar
Abstract
A major challenge for our society is the protection of the environment. Some of the important issues are
the reduction in the consumption of energy and natural raw materials, as well as the increase in
consumption of waste materials. The use of molasses from sugarcane industry in construction, as
alternative to chemical admixtures (water reducing admixtures), has strong potential. The use of
molasses preserves natural resources and reduces the space required for the disposal of sugarcane
industrial wastes in other purposes like production of Bio-ethanol. It might be an important breakthrough
for our society in our attempt towards sustainable development. Much research on the uses of molasses
has been performed during the last few decades. In fact, most of them showed that the molasses is
adequate for use in structural concrete although the behaviour of cement mortars with a wide range of
molasses dosage has not been explored which is very important in choosing the dosage for maximum
mechanical strength and durability performance. Furthermore, no literature is available regarding the
usage of locally source molasses as admixture in concrete yet the composition of molasses may differ
from on region to another. From this point of view, the available literature from other regions can be
misleading if based on to apply locally sourced sugarcane as admixtures. Therefore, the aim of this
study is to evaluate the performance of using locally sourced sugarcane molasses in cement mortar as a
plasticizer admixture based on its consistence and strength properties. Studies were carried out on three
different types of cement mortar mixes i.e., 1:3, 1:4 and 1:6 with and without the use of molasses. In
present work, the molasses were collected from Kakira sugar factory. The effects of different dosages
level 0, 0.01, 0.05, 0.1, 0.50 and 1.00% by weight of cement of the molasses were studied for water
reduction behavior in fresh cement mortar and strength characteristics in hardened cement mortar. The
effect of molasses on 7-day and 28-day compressive strength and 28-day flexural tensile strength of the
different cement mortar mixes under same workability conditions were studied. The tests on mortar were
carried out in accordance with BS EN 1015-3 for workability measurement and BS EN1015-11 for the
flexural and compressive strength check. The test results showed an increase in water reduction with an
increase in molasses content. Further, it was noted that a water reduction percentage of up to 6.9% could
be achieved at 1% dosage level of molasses for mortar mix ratio of 1:3. A decline in the 7-day
compressive strength with an increase in molasses dosage level was noted. Nevertheless, the 28-day
compressive strength of the different mortar mixes at different dosage levels of molasses was seen to be
higher than that of the control mix. The 28-day flexural strength shown an increase up to 0.1% dosage
level of molasses and then declined up to 1% dosage level for all mix designs. The experimental work
shown that an optimum dose of molasses ranging from 0 - 0.1% can be used to enhance the workability
of cement mortar without compromising on its strength properties