Five types of polyurea elastomers were synthesized by changing the isocyanate component and the mechanical properties of polyurea materials were measured. Fiber-reinforced cement boards(FRCB)strengthened by polyurea w...Five types of polyurea elastomers were synthesized by changing the isocyanate component and the mechanical properties of polyurea materials were measured. Fiber-reinforced cement boards(FRCB)strengthened by polyurea with different formulations were processed, and a series of experiments were carried out on the specimens with gas explosion devices. The results showed that the conventional mechanical properties of different types of polyureas had their own advantages. Based on the gas explosion overpressure criterion, the blast resistances of reinforced plates were quantitatively evaluated,and the best polyurea was selected to guide the formulation design. The three typical failure modes of polyurea-reinforced FRCBs were flexural, shear, and flexural-shear failure. Dynamic thermodynamics and shock wave spectral analysis revealed that the polyurea did not undergo a glass transition in the gas explosion tests but retained its elastic properties, allowing it to effectively wrap the fragments formed by the brittle substrates.展开更多
Among the major challenges facing the modern era of technological and industrial advancements are pollution and exponentially growing energy consumption.Pollution continues to be a menace affecting different aspects o...Among the major challenges facing the modern era of technological and industrial advancements are pollution and exponentially growing energy consumption.Pollution continues to be a menace affecting different aspects of life such as health,productivity,and comfort.This paper focuses on the elimination or reduction of sound pollution in buildings using cement-based boards made from pretreated coconut coir and oil palm fibers obtained from agricultural residues.The study includes an account of the preparation of fiber cement boards made from Portland cement Type 1,limestone powder,water,sand,and pretreated coconut coir and oil palm fibers at 5,10,15,and 20%by weight of powder materials,respectively,and a high-range water reducer in order to make sure that the natural materials would be spread in an even way throughout the specimens.Sound insulation tests were performed as key indicators of the performance of the fiber cement boards.It was found that an increase in the proportion of natural materials resulted in fiber cement boards with decreased density,compressive strength,and flexural strength.Furthermore,in relation to both physical and mechanical performance,the boards incorporating coconut fibers were superior to those incorporating oil palm fibers.With an increased proportion of natural fibers,sound insulation performance tended to improve.The boards prepared with coconut coir and oil palm fibers in this study yielded acceptable physical and mechanical properties and showed promise in relation to providing insulative protection against sound.展开更多
基金funded by National Natural Science Foundation of China(No.12002392).
文摘Five types of polyurea elastomers were synthesized by changing the isocyanate component and the mechanical properties of polyurea materials were measured. Fiber-reinforced cement boards(FRCB)strengthened by polyurea with different formulations were processed, and a series of experiments were carried out on the specimens with gas explosion devices. The results showed that the conventional mechanical properties of different types of polyureas had their own advantages. Based on the gas explosion overpressure criterion, the blast resistances of reinforced plates were quantitatively evaluated,and the best polyurea was selected to guide the formulation design. The three typical failure modes of polyurea-reinforced FRCBs were flexural, shear, and flexural-shear failure. Dynamic thermodynamics and shock wave spectral analysis revealed that the polyurea did not undergo a glass transition in the gas explosion tests but retained its elastic properties, allowing it to effectively wrap the fragments formed by the brittle substrates.
文摘Among the major challenges facing the modern era of technological and industrial advancements are pollution and exponentially growing energy consumption.Pollution continues to be a menace affecting different aspects of life such as health,productivity,and comfort.This paper focuses on the elimination or reduction of sound pollution in buildings using cement-based boards made from pretreated coconut coir and oil palm fibers obtained from agricultural residues.The study includes an account of the preparation of fiber cement boards made from Portland cement Type 1,limestone powder,water,sand,and pretreated coconut coir and oil palm fibers at 5,10,15,and 20%by weight of powder materials,respectively,and a high-range water reducer in order to make sure that the natural materials would be spread in an even way throughout the specimens.Sound insulation tests were performed as key indicators of the performance of the fiber cement boards.It was found that an increase in the proportion of natural materials resulted in fiber cement boards with decreased density,compressive strength,and flexural strength.Furthermore,in relation to both physical and mechanical performance,the boards incorporating coconut fibers were superior to those incorporating oil palm fibers.With an increased proportion of natural fibers,sound insulation performance tended to improve.The boards prepared with coconut coir and oil palm fibers in this study yielded acceptable physical and mechanical properties and showed promise in relation to providing insulative protection against sound.
