Influence of Wheat Straw Ash as Partial Substitute of Cement on Properties of High-Strength Concrete Incorporating Graphene Oxide

Abstract

The worldwide move to the utilization of sustainable/green materials has motivated the drive for the use of different supplemental materials in the field of structural application. Further, the utilization of nano-materials has also been amplified for improving concrete properties. The present study mainly emphasizes the strengthening influence of graphene oxide on high-strength concrete cast in the presence and absence of wheat straw ash. Portland cement was substituted with 15% wheat straw ash (WSA) by cement weight. Graphene oxide was included in various doses of 0.020%, 0.040%, 0.060%, and 0.080% by cement weight. Properties of nano-engineered samples were assessed in terms of mechanics (compressive, split tensile, and flexural strength), durability (acid resistance, rapid chloride ions, water absorption, and sorptivity), and x-ray diffraction (XRD) test. The test outcome showed that the mechanical and durability performance of high-strength concrete improved considerably on the inclusion of graphene oxide and was further enhanced through the fractional substitution of cement with 15% wheat straw ash. The optimal behavior in terms of durability and mechanical performance was obtained by a combination of 15% wheat straw ash and 0.060% graphene oxide, which improved compressive strength to 57.3 MPa and split tensile and flexural strength by 33% and 49%, and reduced water absorption, sorptivity, and resistance against acid to 14%, 21%, and 5.6%. Incrementing the dose of graphene oxide to more than 0.060% led to a decline in mechanical strength and durability behavior. Moreover, the XRD showed that samples comprising both wheat straw ash and graphene oxide displayed dense concrete by consuming Ca(OH)2 and forming an extra gel of calcium silicate hydrate in the matrix, which concludes the application of utilizing graphene oxide and wheat straw ash in high-strength concrete.