Comparison between Conventional Method and Cradle-to-Cradle Method of Waste Management Method

Abstract

 Concrete is a widely used material in the construction industry. Rice husk
ash and coal bottom ash are by-product materials chosen to alternate the use of cement
and sand in concrete production. Concerns about the long-term performance of
seawater concrete structures incorporated with RHA-CBA have been obstacles to the
developing uses of sustainable concrete due to the scarcity of knowledge and test data.
Thus, the long-term performance of seawater concrete consisting of RHA as cement
replacement and CBA as sand replacement on compressive strength and carbonation
was evaluated in this study. To accomplish the study's goal, existing specimens aged
1 year and 4 months, and 2 years with different mixture series were used. In the
mixture, seawater was utilized to fully replace freshwater, along with 10% RHA used
to replace cement. Additionally, 10% to 100% CBA replaced the sand with a 10%
increment. The specimens consisted of 68 cylindrical concretes in 100  100 mm and
100  200 mm exposed to indoor environmental conditions. Compressive strength
and carbonation tests were performed to assess the strength and durability of the
concrete. The results indicate that the concretes' strength grows insignificantly in the
atmospheric environment within exposure age. After a prolonged period, the
specimen's strength development reduces as the amount of CBA in the concrete
mixture increases. Meanwhile, test results revealed that RHA-seawater concrete
containing CBA exhibited minimal carbonation after 2 years of aging. Higher
incorporation of CBA in the concrete mixture leads to a greater carbonation rate,
reducing the concrete’s alkalinity. The findings of this study contribute to the
understanding and advancement of long-term performances of sustainable concrete
materials for construction practices.