Nghiên cứu lý thuyết và thực nghiệm về mô men kháng nứt của dầm geopolymer cốt thép

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Tác giả: Quang Đạo Phạm, Thanh Tùng Phạm

Ngôn ngữ: Vie

Ký hiệu phân loại:

Thông tin xuất bản: Tạp chí Khoa học Công nghệ Xây dựng 2020

Mô tả vật lý: 14-25

Bộ sưu tập: Metadata

ID: 409505

Thêm vào giỏ Liên kết toàn văn

Bê tông geopolymer (GPC) là bê tông sử dụng chất kết dính từ tro bay và xỉ lò cao, được hoạt hóa bằng dungdịch kiềm để thay thế xi măng. Đây là loại vật liệu mới có đặc tính kỹ thuật tốt và thân thiện với môi trườnghơn so với bê tông xi măng truyền thống. Hiện nay tại Việt Nam có ít nghiên cứu cơ bản về đặc tính kỹ thuậtcủa bê tông geopolymer cũng như nghiên cứu ứng dụng vật liệu này cho kết cấu xây dựng. Trong bài báo này,nhóm tác giả đề xuất hệ sốγcó xét đến biến dạng dẻo của bê tông vùng kéo khi tính toán mô men kháng nứtcủa dầm bê tông geopolymer cốt thép bằng việc sử dụng mô hình ứng suất - biến dạng của bê tông theo TCVN5574:2018. Kết quả cho thấy hệ sốγđược tính từ hệ số đàn hồi của bê tông chịu kéo lấy theo cường độ chịunén của bê tông geopolymer. Kết quả nghiên cứu lý thuyết được kiểm chứng bởi một chương trình thí nghiệmtrên 9 dầm bê tông geopolymer cốt thép do tác giả thực hiện cũng như với kết quả thí nghiệm trên 25 dầm bêtông của các nghiên cứu khác đã được công bố trên thế giới, Tóm tắt tiếng anh, Geopolymer concrete (GPC) uses an alternative binder that bases on a mixture of fly ash and ground blast furnace slag activated by alkaline solution as a placement of cement. This material shows excellent engineering performance and friendly to the environment in comparison to ordinary cement. Currently, in Vietnam, there is a modest number of fundamental researches on the geopolymer mechanical properties and application of this novel material in the building structures as well. The paper presents the study on the coefficient , that accounts for the plastic deformation in the tensile zone in the calculation of the cracking moment for reinforced GPC beams based on the stress-strain model of concrete in the current standard TCVN 5574:2018. It is shown that this coefficient depends on the elastic coefficient of the concrete in tension taken by the compressive class of GPC. The theoretical approach is verified by experimental works that consist of testing on the behaviour of 9 reinforced GPC beams by the author and also a series of experimental results of 25 reinforced concrete beams published by other researchers over the world.

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