Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Geopolymer

Investigating the Effect of Different Parameters on Physical Properties of Metakaolin-Based Geopolymers

Ahmed J. Abed AL-Jabar; Hanna A. Al-Kaisy; Sarmad I. Ibrahim

Engineering and Technology Journal, 2022, Volume 40, Issue 12, Pages 1-10
DOI: 10.30684/etj.2022.132691.1138

Recently, geopolymers have received widespread attention due to their ability to completely replace ordinary cement with better efficiency, lower cost, and less damage to the climatic environment. This paper aimed to prepare MK-based geopolymer cement at ambient temperature with different alkaline activators and processing parameters. XRD, PSA, DTA-TGA, SEM, and other techniques have characterized the prepared samples. ANOVA test was employed to identify the main effect of the processing parameters. Results showed that the incorporation of potassium ions has a negative effect on the physical properties of GP, in which the presence of such ions tends to decrease the density of GP. Furthermore, the apparent porosity and water absorption were increased. For Na and K, Na-activated GP, it was also concluded that the density of GP increases by increasing Si/Al ratios. Despite the Na-based GP processes having a larger density in compared to the K, Na-based ones. The results also suggested a strong effect of the W\MK ratio on physical properties, in which decreasing this ratio is necessary to achieve GP with better properties. The findings also revealed that a one-minute mixing period was sufficient for producing a homogeneous and dense GP paste.

Effect of Ordinary Portland Cement on Some Properties of Pervious Geopolymer Concrete

Wasan I. Khalil; Qais J. Frayyeh; Haider T. Abed

Engineering and Technology Journal, 2021, Volume 39, Issue 4A, Pages 668-674
DOI: 10.30684/etj.v39i4A.1793

In this research, a study is made on the Pervious Geopolymer Concrete (PGC), which is based on local material (Metakaolin). The inclusion of Ordinary Portland Cement (OPC) as a partial substitute for Metakaolin (MK) for the production of (PGCs) has also been investigated. Pervious Geopolymer concrete was outputted from the local Metakaolin (MK), and ordinary Portland cement (OPC) as a partial substitute by weight of MK and silicate of sodium (Na2SiO3) and hydroxide of sodium (NaOH) solution. All PGC samples were cured after 24 hours from casting for five hours at a temperature degree of 50 ° C, then they tested after 28 days. The compressive-strength, total content of voids, the strength of bending, dry-density, and thermal-conductivity of pervious Geopolymer concrete were examined. The mechanical results of testing ranged from (11.03 and 2.25) to (14.3 and 2.75) MPa for compressive-strength and flexural strength respectively.

Performance of Geopolymer Concrete Exposed to Freezing and Thawing Cycles

Mohammed H. Shamsa; Basil S. Al-Shathr; Tareq S. al-Attar

Engineering and Technology Journal, 2019, Volume 37, Issue 3A, Pages 78-84
DOI: 10.30684/etj.37.3A.1

In this study, the effect of rapid freezing and thawing (ASTM C666 – procedure A) on three different types of Geopolymer concrete studied using three types of pozzolanic material: fly ash, metakaolin and ground granulated blast furnace slag (GGBFS). The Geopolymer concrete was prepared using 400 kg of the pozzolanic material with alkaline liquid prepared at 8 molar concentration with normal fine and coarse aggregates. The ratio of alkaline to fly ash and GGBFS was 1.5: 1 and for metakaolin was 2: 1 for workability and compressive strength requirements. Specimens (100 × 100 × 400) mm were exposed to 100, 200 and 300 cycles of freezing and thawing. The decrease in measured compressive strength was (23, 43, and 26%) for Fly ash, metakaolin and GGBFS respectively. The investigated types of concrete showed good resistance to freezing and thawing. The durability factor of these types was (77%, 68%, and 81%) for fly ash, metakaolin, and GGBFS respectively.