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Effect of Polypropylene Fiber and Curing on the Unconfined Compressive Strength of Geopolymer Stabilized Kaolin Clay
Soft or highly compressible soils often undermine the stability and overall integrity of structures through excessive shear failure and settlement. Past research efforts have established the effectiveness of Ordinary Portland Cement (OPC) binder in improving the strength of these highly soft or compressible soils. Unfortunately, a pronounced shortcoming of OPC is its energy-intensive production, and large quantities of CO2 emissions. This environmental concern has led to the use of geopolymers as a viable alternative to OPC with desirable properties such as high strength and low-energy consumption. The present study investigates the effect of polypropylene fiber (PF) and curing methods on the Unconfined Compressive Strength (UCS) of geopolymer stabilized kaolin clay. The kaolin clay was infused with 20% fly ash and varying PF percentages 0.25%, 0.5%, and 1.0% by dry weight of clay. The alkali precursor NaOH:Na2SiO3 was prepared at a ratio of 1.5:1.0 and molarity of 8 M used for the geopolymer synthesis. Two curing methods were employed, that is, Ambient Curing Temperature (ACT, 23°C) and Elevated Curing Temperature (ECT, 70°C) for a period of 7 and 28 days. Results showed a maximum 28-day UCS value of 32.28 MPa for curing at ECT. This clearly shows that geopolymer-stabilized kaolin clay exhibits a significant increase in 28-day strength under sustained ECT compared to ACT. Hence, ECT was found to be more effective with increasing curing period and PF content compared to ACT. However, the maximum UCS was attained at a 0.25% PF content for ACT and 1.0% for ECT; beyond 0.25% PF, the UCS decreased under ACT, while under ECT, the peak UCS was recorded at 1.0% PF. Scanning Electron Microscope (SEM) test was also conducted to analyze the microstructure of the virgin and geopolymer-stabilized kaolin clays.
Effect of Polypropylene Fiber and Curing on the Unconfined Compressive Strength of Geopolymer Stabilized Kaolin Clay
Soft or highly compressible soils often undermine the stability and overall integrity of structures through excessive shear failure and settlement. Past research efforts have established the effectiveness of Ordinary Portland Cement (OPC) binder in improving the strength of these highly soft or compressible soils. Unfortunately, a pronounced shortcoming of OPC is its energy-intensive production, and large quantities of CO2 emissions. This environmental concern has led to the use of geopolymers as a viable alternative to OPC with desirable properties such as high strength and low-energy consumption. The present study investigates the effect of polypropylene fiber (PF) and curing methods on the Unconfined Compressive Strength (UCS) of geopolymer stabilized kaolin clay. The kaolin clay was infused with 20% fly ash and varying PF percentages 0.25%, 0.5%, and 1.0% by dry weight of clay. The alkali precursor NaOH:Na2SiO3 was prepared at a ratio of 1.5:1.0 and molarity of 8 M used for the geopolymer synthesis. Two curing methods were employed, that is, Ambient Curing Temperature (ACT, 23°C) and Elevated Curing Temperature (ECT, 70°C) for a period of 7 and 28 days. Results showed a maximum 28-day UCS value of 32.28 MPa for curing at ECT. This clearly shows that geopolymer-stabilized kaolin clay exhibits a significant increase in 28-day strength under sustained ECT compared to ACT. Hence, ECT was found to be more effective with increasing curing period and PF content compared to ACT. However, the maximum UCS was attained at a 0.25% PF content for ACT and 1.0% for ECT; beyond 0.25% PF, the UCS decreased under ACT, while under ECT, the peak UCS was recorded at 1.0% PF. Scanning Electron Microscope (SEM) test was also conducted to analyze the microstructure of the virgin and geopolymer-stabilized kaolin clays.
Effect of Polypropylene Fiber and Curing on the Unconfined Compressive Strength of Geopolymer Stabilized Kaolin Clay
Disu, Adedeji A. (author) / Kolay, Prabir (author) / Puri, Vijay (author) / Kumar, Sanjeev (author)
Geo-Congress 2022 ; 2022 ; Charlotte, North Carolina
Geo-Congress 2022 ; 148-156
2022-03-17
Conference paper
Electronic Resource
English
British Library Conference Proceedings | 2022
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