Synergistic Use of Fly Ash and Silica Fume to Produce High-Strength Self-Compacting Cementitious Composites

Abstract

High-performance cementitious composites with self-compacting characteristics are gaining due importance in meeting the challenges of the modern world. This experimental study deals with developing high-strength self-compacting cement mortar composites containing a binary blend of silica fume and fly ash. Seven specimens series were prepared with fly ash (FA), ranging from 17.5% to 25%, and silica fume (SF), from 1.25% to 7.5% of the cement mass. The control specimen powder content consists of 80% ordinary portland cement (OPC), 20% FA, and 0% SF; in the remaining six series of specimens, OPC is kept constant, whereas FA is reduced by 1% and SF is increased by 1% subsequently. Rheological behavior, mechanical properties, and microstructural characteristics of the developed high-performance composites were evaluated. The optimum binary blend for achieving the maximum flow spread and flow rate of the cement mortar is reported as 80% FA and 20% SF. For superior mechanical characteristics, optimum powder content was found as 80% OPC, 17.5% FA, and 2.5% SF. Using the proposed binary blend for construction applications will produce high-strength composites and promote sustainable development due to the use of industrial wastes as OPC replacement.

Some Properties of Self-Compacting Concrete with Optimum Percentages of Cement Replacement Materials

“…This might be due to combined actions of extremely fine particle size of silica fume (high surface area) and fly ash filling effect as well as silica fume pozzolanic activity (Arshad et al, 2021). However, the exact values of cement replacement by these two materials were identified in this study.…”

“…Much investigation has recently been conducted using a combination of these two by-products. (Arshad et al, 2021), used seven specimen series made with FA ranging from (17.5% to 25%) and SF varying from (1.25% to 7.5%) of the cement weight. The binder content of the control specimen is 80% OPC, 20% FA, and 0% SF.…”

Efek Pemanasan Terhadap Kuat Tekan Mortar Semen Dengan Penambahan Fly Ash

“…Limbah padat ini berupa bottom ash dan fly ash dengan kandungan 80-90% berupa bottom ash dan sisanya 10-20% berupa fly ash (Haryanti, 2014). Penanganan limbah ini tidak secara khusus, tapi diletakkan pada areal terbuka, salah satu bentuk penanganannya adalah dengan memanfaatkan sebagai bahan tambah pada bidang teknik sipil seperti pada campuran beton dan mortar (Arshad et al, 2021;Gopalakrishnan, 2018;Kabir et al, 2018;Sultan & Hakim, 2020). Beberapa peneliti telah mengaplikasikan penggunaan fly ash sebagai bahan perekat menggantikan semen secara parsial, konsentrasi 30% sebagai pengganti semen memberikan kekuatan optimum sebagai bahan perekat bata ringan (Karijanto et al, 2013).…”

Efek Penambahan Fly Ash Terhadap Kuat Tekan Mortar Semen

“…Limbah yang dihasilkan oleh PLTU umumnya diletakkan pada lahan terbuka sehingga berpotensi untuk mencemari lingkungan sekitarnya. Salah satu penangan limbah ini adalah dengan memanfaatkan sebagai campuran pada beton atau mortar, mengingat fly ash memiliki sifat cementitious (Ammasi & Ragul, 2018) (Arshad, Ahmad, Khitab, & Hanif, 2021). Pada penggunaan fly ash sebagai campuran pada beton atau mortar mempunyai keuntungan yaitu dapat memperbaiki sifat beton atau mortar tersebut.…”