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Filler Effect of Pozzolanic Materials on the Strength and Microstructure Development of Mortar
M. N. N. Khan,M. Jamil,M. R. Karim,M. F. M. Zain,A. B. M. A. Kaish 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.1
The utilization of pozzolans in cementitious system (concrete and mortar) minimizes both cost and energy. It also enhances mechanical strength and durability of the system. The total contribution of pozzolans can be categorized into two: (i) physical or filler effect which is attributed by the fineness of the particles and (ii) chemical or pozzolanic effect which is attributed by the pozzolanic reaction. It is difficult to quantify the strength development of cementitious system caused by the filler and pozzolanic effect separately. Therefore, the individual contribution of pozzolans in cementitious system because of its physical and chemical effects need to be profoundly understood by the scientific community. This paper reviews available literatures to understand the effect of non-reactive fillers that attributed as the microfiller effect of pozzolans in cementitious systems. The previous studies utilized chemically inactive materials that attributed only the microfiller activity of pozzolans for a partial replacement of cement. It was reported that filler effect is equal or sometimes more significant than pozzolanic effect in concrete. A larger range of replacement percentages (like 5%, 10%, 15% or 10%, 20%, 30% etc.) was used in the previous studies. However, probabilities of the optimum compressive strength because of the filler effect may lie in between two larger range of replacement percentages. Therefore, an experimental work is also carried out using natural ground sand of size 7.6-μm at a lower range of cement replacement percentages (like 2.5%, 5%, 7.5% etc.) in mortar. Compressive strength of mortar at different ages and microstructure analysis of mortar at 28 days were performed in this study. Test results showed that the filler effect is more pronounced at a lower replacement percentages of cement (0-10%) while using smaller non-reactive fillers. The maximum strength due to filler effect of ground sand is acheieved at 7.5% replacement of cement. Scanning Electron Microscope (SEM) images also confirmed the effect of fillers on the microstructure development of mortar.
Building structural health monitoring using dense and sparse topology wireless sensor network
Mohammad E. Haque,Mohammad F.M. Zain,Mohammad A. Hannan,Mohammad H. Rahman 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.16 No.4
Wireless sensor technology has been opened up numerous opportunities to advanced health and maintenance monitoring of civil infrastructure. Compare to the traditional tactics, it offers a better way of providing relevant information regarding the condition of building structure health at a lower price. Numerous domestic buildings, especially longer-span buildings have a low frequency response and challenging to measure using deployed numbers of sensors. The way the sensor nodes are connected plays an important role in providing the signals with required strengths. Out of many topologies, the dense and sparse topologies wireless sensor network were extensively used in sensor network applications for collecting health information. However, it is still unclear which topology is better for obtaining health information in terms of greatest components, node\'s size and degree. Theoretical and computational issues arising in the selection of the optimum topology sensor network for estimating coverage area with sensor placement in building structural monitoring are addressed. This work is an attempt to fill this gap in high-rise building structural health monitoring application. The result shows that, the sparse topology sensor network provides better performance compared with the dense topology network and would be a good choice for monitoring high-rise building structural health damage.
Mohamad Azuwa Mohamed,M. F. M. Zain,Lorna Jeffery Minggu,Mohammad B. Kassim,Juhana Jaafar,Nor Aishah Saidina Amin,Mohd Sufri Mastuli,Hao Wu,Roong Jien Wong,Yun Hau Ng 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.77 No.-
The in-situ hierarchical heterojunction photocatalyst consists of C-doped g-C3N4 (CCN) grafted on the C, Nco-doped ZnO were successfully realized via simple bio-template hydrothermal approach. The resultantshierarchical heterojunction photocatalyst exhibited excellent UV to the near infrared absorptioncapability. The electrochemical analysis and photoluminescence spectroscopy revealed that thehierarchical heterojunction photocatalyst possessed excellent charge generation and separationefficiency. The resultant hierarchical heterojunction photocatalyst exhibited remarkable photocatalyticperformance in the photodegradation of bisphenol A and photocatalytic hydrogen evolution undersimulated solar irradiation. The enhancement of photocatalytic performance was mainly attributed tothe combined effect of hierarchical morphology, in-situ doping, and heterojunction formation.