School of Civil Engineering, Universiti Sains Malaysia, 14300, Nibong Tebal, Penang, Malaysia.
Civil Engineering Department, Faculty of Engineering Sabratha, Sabratha University, Sabratha, Libya.
Environ Sci Pollut Res Int. 2022 Oct;29(48):72493-72514. doi: 10.1007/s11356-022-20710-3. Epub 2022 May 24.
The current study aims to explore the impact of palm oil fuel ash (POFA) heat treatment on the strength activity, porosity, and water absorption of cement mortar. The cement mortar mixtures were typically comprising cement or cement in combination with ultrafine treated POFA (u-TPOFA) which is the final form of the treated POFA, sand, water, and a superplasticizer. Before utilizing the u-TPOFA in mortar mixtures, the treatment processes of POFA were undertaken via five steps (drying at 105 ℃, sieving, grinding, heat treatment, re-grinding) to form u-TPOFA. The heat treatment was performed at three different heating temperatures (i.e., 550 ℃, 600 ℃, and 650 ℃). The ratio on mass/mass basis of the blended ordinary Portland cement (OPC) with u-TPOFA was OPC:u-TPOFA of 70%:30%. A total of four mixtures were prepared, consisting of a plain control mixture (designated as PCM) and three mixtures containing 30% of u-TPOFA treated at three different temperatures designated as M1 "550 ℃," M2 "600 ℃," and M3 "650 ℃". The results show that the optimum mixture was M2 which achieved the highest strength activity index (SAI) of 101.84% and 107% among all mixtures at 7 days and 28 days, respectively. Meanwhile, the porosity (P%) and water absorption (Abs%) of M2 exhibited the lowest values of 9.3% and 4.5%, respectively, among all the mixtures at 28 days. This superior performance of u-TPOFA treated at 600 ℃ represented in the M2 mixture was due to the formation of more binding phases consisting of calcium silicate hydrate (C-S-H) type gel originated from a higher pozzolanic reaction and the filler effects caused by the fine u-TPOFA microparticles. These observations were further confirmed by the improved performance of the M2 mix among all the designed mixes which also exhibited better results in terms of bulk density (BD), ultrasonic pulse velocity (UPV), X-ray diffraction (XRD) as well as thermogravimetry (TGA) and field emission scanning electron microscopy (FESEM-EDX) analyses.
本研究旨在探讨棕榈油燃料灰（POFA）热处理对水泥砂浆强度活性、孔隙率和吸水率的影响。水泥砂浆混合物通常由水泥或水泥与超细处理 POFA（u-TPOFA）组成，u-TPOFA 是处理 POFA 的最终形式，还包括沙子、水和高效减水剂。在将 u-TPOFA 用于水泥砂浆混合物之前，先通过五个步骤（在 105℃下干燥、筛分、研磨、热处理、再研磨）对 POFA 进行处理，以形成 u-TPOFA。热处理在三个不同的加热温度（即 550℃、600℃和 650℃）下进行。混合普通波特兰水泥（OPC）与 u-TPOFA 的质量比为 OPC：u-TPOFA=70%：30%。共制备了四种混合物，包括一种普通对照混合物（标记为 PCM）和三种含有 30%u-TPOFA 的混合物，分别标记为 M1“550℃”、M2“600℃”和 M3“650℃”。结果表明，最优混合物是 M2，在 7 天和 28 天分别达到 101.84%和 107%的最高强度活性指数（SAI）。同时，在 28 天时，M2 的孔隙率（P%）和吸水率（Abs%）分别为所有混合物中的最低值，分别为 9.3%和 4.5%。在 M2 混合物中，600℃下处理的 u-TPOFA 表现出优异的性能，这是由于形成了更多的结合相，包括由更高的火山灰反应和细 u-TPOFA 微粉的填充效应产生的硅酸钙水合物（C-S-H）型凝胶。这些观察结果进一步通过 M2 混合物在所有设计混合物中的性能得到了证实，该混合物在堆积密度（BD）、超声波脉冲速度（UPV）、X 射线衍射（XRD）以及热重分析（TGA）和场发射扫描电子显微镜（FESEM-EDX）分析方面也表现出了更好的结果。
