THE EFFECT OF THE COMBINATION ADDITIVE ADMIXTURES TO INCREASE SETTING TIME AND COMPRESSIVE STRENGTH AT THE CONCRETE CASTING IN WARM TROPICAL TEMPERATURE

Every time in casting's concrete in warmer tropical temperatures, concrete setting time is needed to support the concrete's workability. The concrete casting needs an additional setting time by adding silica fume (SF), fly ash (FA), or add other materials. This study attempts to use Coca-Cola as the supporting material to determine the setting time of concrete by combining Coca-Cola and Plastocrete® RT6 plus, which are done to show the improved setting time and concrete compressive strength. This idea began with the concept of sugar content in Coca-Cola, which is very high, and plastocrete® RT6 plus is an additional ingredient to increase setting time and concrete compressive strength. The authors are inspired to take both of the benefits of these ingredients by combining the Plastocrete® RT6 plus 0.35% and Coca-Cola 0.15% from total weight of the cement and reducing the amount of cement used by 11%. The results of the combination revealed the setting time of concrete increased by 54.6% longer than normal concrete with less usage of cement and increasing the concrete compressive strength by 1,6%. If the amount of the cement in concrete mix is not reduced, the concrete compressive strength is 3.2% higher than the normal concrete. Subsequently, the addition of those materials is not only to delay the concrete setting time but they are also significantly increasing the concrete compressive strength, and become the alternative to decrease cement usage. The highlights are the additional materials as a problem solver for concrete casting in tropical areas and a few areas that needed a longer setting time. This method has been implemented in some building construction of Mulawarman University, Samarinda, Indonesia