Utilization of Industrial Waste in Cement in a Marine Environment with a Tropical Climate

Abstract

This novel study on cement paste material was conducted with the aim of keeping up with the rapid development of urban construction and contributing to the continuous improvement of building materials to overcome environmental issues. In this study, several kinds of industrial waste were used to enhance the properties of cement paste for application in a marine environment with a tropical climate, such as in Vietnam. This study focuses on evaluating the properties of cement paste containing cement replacement combining 0-30% fly ash, 0-10% silica fume, and plasticizer accounting for 0.3% and 0.4% of the binder by mass. Water demand, chloride ion and sulfate ion permeability, and microstructural properties of the cement paste were determined by thermogravimetric analysis (TGA), X-ray diffraction (XRD), and scanning electron microscope (SEM) and they were investigated after 28 and 56 days. The test results show that an optimum mixture could be obtained with the use of 20% fly ash, 10% silica fume (replacing Portland cement), and 0.4% plasticizer. The application of such materials to sea dikes affected by a tropical climate (characterized by heat, humidity, salty seawater, many big storms, large waves, and strong tides) was investigated for four years on the Vietnamese coast. The test results indicate that fly ash and silica fume can improve the corrosion and abrasion resistance of concrete in coastal areas with a tropical climate, such as in Vietnam.

Engineering, Durability, and Sustainability Properties Analysis of High-Volume, PCC Ash-Based Concrete

“…This result is similar to some studies that showed satisfactory performance in terms of resistance to cyclic freezing and thawing, and deicer salt scaling when PCC ash was replaced by 30% or more [54,55]. In addition, according to the study of Chu et al (2019) [26], the samples with PCC ash had a lower rate of chloride ion and sulfate ion permeability than the control group. The reason is that the presence of PCC ash increases the amount of C3A due to the higher amount of alumina present in the mixture.…”

“…In addition, there are also research results focusing on the durability of PCC ash concrete as follows. Chuet al (2019) [26] conducted experiments with PCC ash 0~30%, silica fume 0~10%, plasticizer 0.3% and 0.4%, to examine cement pastes for application in tropical climate marine environments such as Vietnam. As a result of the test, the optimum formulation was analyzed to be 20% PCC ash, 10% silica fume, and 0.4% plasticizer.…”

Determining the Mineral Admixture and Fiber on Mechanics and Fracture Properties of Concrete under Sulfate Attack

“…Based on the defects of concrete materials, exploring and researching new materials and technologies that improve the corrosion resistance of concrete has become a research hotspot. Adding an appropriate amount of admixtures to ordinary concrete components for modification is a more economical way to improve the durability of concrete structures [12]. Fracture mechanics, also called "crack body mechanics", is a discipline that studies the strength of components working with defects or cracks.…”

Avaliação do potencial de uso da cinza de >i<Sargassum>/i< spp. como adição mineral em compósitos de cimento Portland

“…Com a adição de cinzas nas pastas cimentícias, observa-se um aumento da perda de água, pois as cinzas da alga de sargaço podem reter partículas de água em seus poros capilares. Além disso, pode ocorrer a desidratação de gel C-S-H e a decomposição de C-S-H sobrepostos com hidratos de sulfoaluminato de cálcio (hidratos de etringita e monossulfato), desidroxilação de CH, bem como produtos de hidratação, os hidratos de aluminossilicato de cálcio (CHU et al, 2019). Dessa forma, observa-se maior decomposição de produtos de hidratação da pastas cimentícias com 10% de cinzas de sargaço.…”

“…As amostras das pastas apresentaram comportamentos semelhantes nas análises de difração de raios X, na Figura 24. Observa-se, na Figura 24, na faixa demarcada (30°-35°), as pastas cimentícias com a adição de cinzas de sargaço, o pico de portlandita Ca(OH)2 diminui em intensidade à medida que o nível de acréscimo das cinzas e o aumento da hidratação devido a cinza de sargaço absorver umidade (CHU et al, 2019). A formação de portlandita, produto importante na hidratação do cimento, contribui na resistência das pastas.…”