The effect of rice husk ash addition as pozzolan on geopolymer binder using alkali activators

Abstract

Geopolymer concrete is an example of innovative concrete that does not use cement as a binder and generally fly ash used in recent research. However, fly ash is categorized as a hazardous and toxic waste [8]. This research studied about another binder, besides fly ash, in this case is rice husk ash made as a geopolymer paste alkali activated by a chemical mixture of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) confronted to a fly ash mixture paste as comparative material. The compositions made were, 100% rice husk ash, a mixture of 50% rice husk ash and 50% fly ash, and 100% fly ash as control mixture. After making the mixture, the composition will be tested to setting time-test in the form of paste. The size of specimen was cylindrical 2,5 cm in diameter 5 cm in height and cube size 15 cm x 15 cm x 5 cm. Each type of specimen was projected to porosity test, compressive strength test, UPV (Ultrasonic Pulse Velocity) and permeability test on 3 days, 28 days and 56 days of sample’s age. From the result of setting time, it was found that the composition of 100% rice husk ash had the longest on binding, which were 129 minutes for early binding and 170 minutes for late binding. The lowest result of porosity test was 100% of fly ash at 56 days of sample’s age testing with a porosity of 20%. The lowest result of compressive strength was 100% of rice husk ash tested in 3 days of sample’s age showed a compressive strength at 0.65 MPa. Based on the test results of UPV (Ultrasonic Pulse Velocity), the lowest value of wave velocity was 531.667 m/s, belong to 100% rice husk ash mixture at 3 days of sample’s age testing, with very poor binder quality qualification. The test result of highest permeability kT value with very poor-quality index binder was 100% rice husk ash with period of testing time in 3 days 0,047.10-16 m2.

A Review on Mechanical Properties and Sorptivity Coefficient of GGBFS and Fly Ash Based Geo-Polymer Concrete

“…Steam-curing geo-polymer specimens with 100% copper slag tensile and compressive strength were 55.1 and 54.8% higher when compared to the tensile strength during the 28-day curing period (16) . Ash inclusion in geo-polymer concrete in large quantities provides high compressive strength, with 12M molarity and 100% composition of fly ash; the compressive strength was up to 43.32Mpa (17) . As per (18) the effect of heat curing at 1200 C on the strength evolution in brown coal fly ash, the polymerization progressed more rapidly for the mortar specimens than the concrete specimens with 12 to 14 hr providing curing time for 50mm mortar cubes and 24 hr being the optimum time for 100mm concrete cubes.…”

Study of using Coal Fly Ash (CFA) and Rice Husk Ash (RHA) on the Compressive Strength of Geopolymer Concrete

“…ASTM-C618-15 chemical standard for N, F and C classes [11] Rice husk ash has high silica content [12], [13], [14], [15], [16], [17] and has a hydrated amorphous structure. The result of XRD and XRF (Table 3) characterization of rice husk ash in Indonesia from other studies conducted in Surabaya-East Java Province [12], [16], Tangerang Regency-Banten Province [13], Aceh Besar Regency-Nangroe Aceh Darussalam Province [14], Surakarta-Central Java [15], Pekanbaru -Riau Province Sumatera [17]. The XRD characterization from Maulana et al [12] and Hadjasaputra et al [13] shows that RHA mainly consisted of amorphous silica, cristobalite, rutile, and some trace amount of montmorillonite, muscovite, and anorthite.…”

Efek Korosi Tulangan Terhadap Kapasitas Lentur Balok Beton Bertulang

“…Konsekuensi utama dari korosi baja termasuk hilangnya penampang baja, terjadi tekanan ekspansif yang menyebabkan beton retak, terkelupas dan delaminasi selimut beton. Dengan demikian, mengurangi kekuatan ikatan antara tulangan baja dan beton, dan menurunkan kekuatan struktur (Kale & Patil, 2019;Mohd Noh et al, 2018) Degradasi kapasitas lentur struktur beton bertulang berbanding dengan peningkatan korosi karena kapasitas tulangan akan menurun setelah adanya produk karat (Krishna & Sandeep, 2019;M. A. Sultan et al, 2022;M.…”