‘Concrete amount of water need to be

is prepared by mixing water, cement, and aggregate together to make a workable
paste. Water is the most important ingredient in concrete. Water causes the
concrete to harden through a process called hydration. Hydration is a chemical
reaction in which the major compounds in the cement form which is an exothermic
reaction. The concrete needs the moisture to hydrate and cure (harden). When
the concrete has dried out it stops getting stronger. The exothermic reaction
of water and cement is extremely important because the strength of the concrete
is dependent on the hydration reaction, however, the hydration reaction itself
consumes a specific amount of water which makes the water and cement ratio very
important because too little water will make the concrete weak and too much
water will make the concrete unworkable, however concrete is actually mixed
with more water than needed for the hydration reaction. The extra water that is
not consumed in the hydration reaction remains in the microstructure pore space,’
(Matse1.matse.illinois.edu. (2017). Concrete:
Scientific Principles. online) which will make the concrete stronger
because the porosity will be reduced because concrete with high porosity has
lower strength. 




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The aim of this experiment was to determine the effect of
replacing a percentage of OPC with GGBS however there could have been some
errors during the experiment which could have affected the result.


The results could have been affected by lost of product
which could occur whilst measuring and pouring the OPC and GGBS into the tray
some of the product could have been left behind and dusting can occur whilst
dry mixing this could have been sorted by adding a tiny bit more OPC and GGBS
then recommend. Human error could also affect the results because maybe too
much water was added or too less and there needs to be a correct specific
amount of water need to be added otherwise the strength of the cube will be
effected to prevent this from slowly add the water until the mixture is a workable
paste and mix a little longer to make sure the mixture is well combined.


Mixture A had the most OPC and the heat raised until after 3
minutes which dropped by 0.9 and raised after a minute by 0.1 and dropped again
after 5 minutes by 0.1 and stayed at that temperature. Mixture D had the least
amount of OPC and most amount of GGBS the temperature slowly raised for two
minutes by 0.1 and on the 3rd minute stayed constant. Mixture C
raised after two minutes by 0.1 and stayed at that temperature for 9 minutes
then dropped by 0.1. mixture B did not have any dramatic drops like mixture A
it slowly kept on rising then stayed at the same temperature for 4 minutes and
raised again then after two minutes dropped by 0.1.  According to the results mixture B (75% OPC
& 25% GGBS) is the best ratio replacement for cement it had the best heat
of hydration which is necessary for the cube to cure, even though mixture B and
the least amount of water then the rest and mixture D had the most.


The cube cross-sectional area is 10000m2 and the
cube volume is 0.001m3 in cube mass, density the lowest was A4
mixture D and the highest was A2 mixture B the same goes for failing load and
compressive strength. From the result mixture B is the best and that 75% OPC
and 25% GGBS is the best ratio for cement replacement actually even better than
cement alone. Mixture B had the best heat of hydration and was the strongest
cube out of all four.