Performance evaluation of cashew nutshell ash as a binder in concrete production
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Elsevier
Abstract
Description
The agro-industrial sector annually produces large volumes of waste by-products which as
a result of the ignorance of their values as well as their ineffective management, pose
environmental, societal and economic threats. Thus, this study explored the ash from
cashew nutshell waste and replaced it with Portland limestone cement (PLC) at 5%,10%,15%
and 20% using a mix design ratio of grade 25 MPa concrete (M 25). The cashew nutshell was
sun-dried for 14 days and then burnt in a gas furnace at a temperature of 750 �C for 5 h to
obtain cashew nutshell ash (CNSA). The chemical and physical properties of the CNSA were
examined while the workability of the fresh concrete was investigated. Moreover, the
mechanical and durability properties of the hardened concrete were carried out while the
microstructures of the concrete samples were analyzed. The experimental
findings
revealed that CNSA met the requirements for use as a pozzolanic material. The slump and
the compacting factor increased with increasing CNSA content. Moreover, both
compressive, splitting tensile and
flexural strengths of the hardened concrete increased
as the content of CNSA increased but optimum at 15% replacement level. Furthermore, the
CNSA concrete resisted more sulfate attack than the Portland cement concrete (control).
The micromorphological analysis exhibited a reticular structure and adequate
filling ability
with the incorporation of CNSA content in the mix. Hence, it is recommended that CNSA can
be incorporated as a construction material in the concrete production at the optimum
replacement with PLC at 15% for structural application and 20% for non-load bearing
application. This study is advantageous because fresh concrete would remain workable for
longer periods, thus, resulting in the reduction of construction joints. Moreover, the
utilization of CNSA concrete is also beneficial in an environment with high sulfate content.
Finally, the developed model equations from this study can be used in the development of
mix design of blended concrete as well as a better refinement of existing procedure of
concrete mix design provided the chemical composition of the materials is established.
Keywords
TA Engineering (General). Civil engineering (General)