As an alternative to conventional construction material such as normal concrete, waste paper sludge ash (WPSA) based geopolymer is seen as a promising and viable option in construction material selection due to its high amount of aluminum (Al) and silicon (Si) content. This research aims to determine the microstructure and mechanical characteristics of WPSA in geopolymers. The alkaline solution that contains 6 M of sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃) was used to activate the geopolymer. The hardened 50 mm-sized mortars were prepared and underwent a heat-cured process for 1 day at various temperatures at 24 ?, 60 ?, and 90 ?, respectively. Then, the mortar cubes were placed in the laboratory until the testing days. A compression test was conducted to identify the strength development of the WPSA-based geopolymer mortar at 7, 14, and 28 days, respectively. Chemical composition was analyzed using X-ray fluorescence (XRF). Furthermore, Fourier-transformed infrared spectroscopy (FTIR) was conducted to ascertain the structural elucidation and scanning electron microscope (SEM) analysis was done to provide microstructural observations of the geopolymer. Based on the XRF analysis, the WPSA has the highest amount of calcium oxide (CaO) instead of aluminum oxide (Al₂O₃) and silicon dioxide (SiO₂), and it reduces the performance of WPSA as a cement replacement material. The ratio of SiO₂ and Al₂O₃ is recorded as 1.1:1. Therefore, it is suitable for bricks and ceramics production instead of concrete production. As for the curing process, the heat-cured method is evident in accelerating strength development in the WPSA-based geopolymer mortar compared to the ambient curing method due to the rapid polymerization process in the geopolymer system. It is proven that 60 ? is the optimum temperature for the curing process for geopolymer mortar. ABSTRAK: Sebagai salah satu alternatif kepada bahan binaan konvensional seperti konkrit biasa, geopolimer berasaskan abu enap cemar kertas (WPSA) adalah dilihat sebagai pilihan yang baik kerana bahan ini mempunyai kandungan aluminium (Al) and silika (Si) yang tinggi. Penyelidikan ini bertujuan untuk menentukan struktur mikro dan ciri mekanikal WPSA dalam geopolimer. Larutan alkali yang mengandungi 6 M natrium hidroksida (NaOH) dan natrium silikat (Na₂SiO₃) digunakan untuk mengaktifkan geopolimer. Mortar yang bersaiz 50 mm telah disediakn dan ia melalui proses pengawetan haba selama 1 hari pada suhu yang berza-beza, iaitu 24 ?, 60 ?, and 90 ?. Kemudian, kiub mortar tersebut diletakkan di dalam makmal sehingga hari ujian. Ujian mampatan dijalankan untuk mengenal pasti perkembangan kekuatan mortar geopolimer apabila mencapai 7, 14, dan 28 hari. Komposisi kimia dalam sampel telah dianalisa menggunakan pendarfluor sinar-X (XRF). Tambahan pula, Spektroskopi inframerah fourier transformasi (FTIR) untuk memastikan sifat bahan dan analisis pengimbasan mikroskop elektron (SEM) untuk menyediakan pemerhatian struktur mikro geopolimer. Berdasarkan data dari analisa XRF, WPSA mempunyai jumlah kalsium oksida (CaO) tertinggi berbanding aluminium oksida (Al₂O₃) dan silikon dioksida (SiO₂), dan ia mengurangkan prestasi WPSA sebagai bahan gantian simen. Nisbah SiO₂ dan Al₂O₃ direkodkan sebagai 1.1:1. Oleh itu, ia sesuai digunakan untuk pengeluaran batu bata dan seramik berbanding pengeluaran konkrit. Bagi proses pengawetan, kaedah pengawetan haba terbukti mempercepat perkembangan kekuatan geopolimer berasaskan WPSA berbanding pengawetan pada suhu ambien disebabkan berlakunya proses pempolimeran yang sangat pantas dalam sistem geopolimer tersebut. Telah terbukti bahawa suhu 60 ? adalah suhu optimum bagi proses pengawetan mortar geopolimer berasaskan WPSA ini.

Damage due to wind-related disasters is increasing due to global climate change. Many studies have been conducted to study the wind effect surrounding low-rise building using wind tunnel tests or numerical simulations. The use of numerical simulation is relatively cheap but requires very good command in handling the software, acquiring the correct input parameters and obtaining the optimum grid or mesh. However, before a study can be conducted, a grid sensitivity test must be conducted to get a suitable cell number for the final to ensure an accurate result with lesser computing time. This study demonstrates the numerical procedures for conducting a grid sensitivity analysis using five models with different grid schemes. The pressure coefficients (C_P) were observed along the wall and roof profile and compared between the models. The results showed that medium grid scheme can be used and able to produce high accuracy results compared to finer grid scheme as the difference in terms of the C_P values was found to be insignificant.

The aim of this study is to enhance the validation of CFD exercise along the roof profile of a low-rise building. An isolated gabled-roof house having 26.6° roof pitch was simulated to obtain the pressure coefficient around the house. Validation of CFD analysis with experimental data requires many input parameters. This study performed CFD simulation based on the data from a previous study. Where the input parameters were not clearly stated, new input parameters were established from the open literatures. The numerical simulations were performed in FLUENT 14.0 by applying the Computational Fluid Dynamics (CFD) approach based on steady RANS equation together with RNG k- model. Hence, the result from CFD was analysed by using quantitative test (statistical analysis) and compared with CFD results from the previous study. The statistical analysis results from ANOVA test and error measure showed that the CFD results from the current study produced good agreement and exhibited the closest error compared to the previous study. All the input data used in this study can be extended to other types of CFD simulation involving wind flow over an isolated single storey house.

Most Malaysian rural houses are categorized as non-engineered buildings and vulnerable to damage during events such as windstorms due to the fact that these houses lack engineering considerations. These houses are characterized by having an attached kitchen house, and many of these houses were previously damaged by thunderstorms. The current research investigated the air flow characteristics changes surrounding these houses as a result of the presence of the kitchen. The roof pitch, position, gap height, and overhang were investigated using computational fluid dynamics (CFD) simulations. The results showed that the kitchen position at the center resulted in a slight increase in the suction on the ridge of the roof; however, it significantly altered the flow pattern in the windward and leeward directions. The results also showed that the roof overhang, roof pitch, and kitchen position contributed severely to the damage of the rural house. Moreover, the highest suction occurred at the roof ridge when the kitchen was located at the center of the rural house (C_p = −2.28). Therefore, the authors believe that it is more advantageous to have a kitchen connected to the core as it reduces the pressure on the roof of the core during thunderstorm events.

Single-storey houses are classified as low rise building and vulnerable to damages under windstorm event. This study was carried out with the aim to investigate the pressure distribution and streamlines around an isolated house by considering the effect of terrain characteristics. The topographic features such as flat, depression, ridge, and valley, are considered in this study. This simulation were analysed with Ansys FLUENT 14.0 software package. The result showed the topography characteristics influence the value of pressure coefficient and streamlines especially when the house was located at ridge terrain. The findings strongly suggested that wind analysis should include all topographic features in the analysis in order to establish the true wind force exerted on any structure.