Abstract
Decreasing our over-reliance on cement as an ingredient in the making of concrete due to its contribution to the CO2 emissions has led to numerous researches been conducted to find suitable replacement for cement in concrete mixes. Materials like fly ash, ground granulated blast furnace slag, silica fume, rice husk ash and metakaolin among others have been identified as materials that can at the very least be used as a replacement for cement in concrete mix. These materials are referred to as supplementary cementitious materials (SCMs). This paper reviewed the work that has been done on the use of fly ash and rice husk ash as partial replacements for concrete, its chemical composition and its effect on the compressive strength of concrete. Charts, tables and figures were employed as tools to study the various chemical compounds of fly ash and rice husk ash. It was seen that depending on how the coal or rice husk was initially processed the percentage of some of the minor compounds like Sodium oxide (Na2O), Titanium oxide (TiO2) and Phosphorus pentoxide (P2O5) were sometimes very low or not recorded as part of the final product. The data on the compressive strength of concrete after fly ash and rice husk ash had been added in percentage increments of 0%, 10%, 20%, 30%, 40%, 50% and 0%, 5%, 7.5%, 10%, 12.5%, 15% respectively analysed over a minimum period of 7 days and a maximum period of 28 days found out that the optimal percentage partial replacement of fly ash and rice husk ash for a strong compressive concrete strength is 30% of fly ash and 7.5% of rice husk ash.
Highlights
Industrialization and urbanization, population growth, globalization of the economy market and consumerism and environmental pollution are the main factors which contribute to the social and economic changes in the society
This paper reviews the research works done by other researchers by using tables, charts and figures to analyse the chemical compounds of fly ash and rice husk ash and its effect on the compressive strength of concrete after 7, 14 and 28 days after different percentages of fly ash and rice hush ash have been added to concrete as a partial replacement
The need to create environmentally friendly materials which can serve as a partial replacement for cement in concrete mixes has gained a lot of attention due to cement’s contribution to the CO2 emissions
Summary
Industrialization and urbanization, population growth, globalization of the economy market and consumerism and environmental pollution are the main factors which contribute to the social and economic changes in the society. Fly ash (FA), silica fume (SF), ground granulated blast furnace slag (GGBS), metakaolin (MK) and rice husk ash (RHA) among others are some of the mineral admixtures used for cement replacement [11] These are called supplementary cementitious materials (SCMs). The problems associated with the protection of the environment makes using waste a necessary material in the construction and building industry. A lot of developing countries have a problem regarding waste since it results in the rise in pollution This problem could be solved through the recycling of these materials into new construction materials. Research has been intensified in the use of some locally available materials which can serve as partial replacement for cement in construction works due to the need to decrease to huge cost involved in using Ordinary Portland cement in concrete [15]. This paper reviews the research works done by other researchers by using tables, charts and figures to analyse the chemical compounds of fly ash and rice husk ash and its effect on the compressive strength of concrete after 7, 14 and 28 days after different percentages of fly ash and rice hush ash have been added to concrete as a partial replacement
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