Bio-Based Self-Healing Mortar

This paper investigates the effects of alkaliphilic spore-forming bacteria of the genus Bacillus on the compressive strength of the mortar cube and the healing capacity of the bacteria as healing agent on mortar containing crack. The experiments were carried out using cube test, stereomicroscopy and environmental scanning electron microscopy (ESEM). Cracked mortar specimen with and without the presence of the bacteria-healing agent were prepared. Results showed that the inclusion of these bio-healing agent in mortar mixtures cause more pore volume, which has no significant effect on compressive strength development at 28 days. In the series of healing capacity test, the cracks were significantly healed in bacteria-based than in control specimens after 28 days incubated in water bath and thus, increase permeability resistance of bacteria-based mortar specimens

Mechanical properties of low carbon and sustainable building block uitilising oil palm trunk fiber / Mazlina Mohamad, Zakiah Ahmad and Balqis Md Yunus

Cement block has been used in the construction of low-cost housing due to its bigger surface area when compared to brick. Another advantageous of cement blocks is that they require less cement mortar and less labour during construction of housing units. Nowadays cement block weight has been an issue in the construction industry. As the building become higher and enormous, the block weight will become a significant factor in the design and hence as the determinant for the economical factor in the construction cost. Moreover, the use of high cement based building block also reduces the thermal comfort index of the building. In order to overcome this issue, lightweight block will be developed by introducing the use of natural fiber namely oil palm trunk fiber at high percentage in order to reduce the amount of cement and sand. Studies have been conducted on the use of OPTF (Ahmad and Mohd Saman, 2003) for concrete but the percentages used was very little, i.e 5%. The function of the fiber is just to increase the mechanical properties and improve the toughness. This also did not solve the problem of abundance wastage of OPTF at the oil palm plantation. The focus of this project is to show that fibres processed from the trunk of the oil palm tree, can be utilized in the production of bio-cement composite block with satisfactory engineering properties and dimensional stability. In this work; an investigate will be made on the potential of using oil palm trunk fiber in the manufacturing of cement block by adding high percentage of fiber with the addition of foam mortar to enhance the lightness of the block. Studies also include the water absorption characteristics and bondability test between foam cement mortar and fibers. A new shape of block will also be proposed to reduce the use of cement mortar to connect individual unit and longer man-hours during construction

Test methods to determine durability of concrete under combined environmental actions and mechanical load: final report of RILEM TC 246-TDC

At present several methods are available to predict the durability of reinforced concrete structures. In most cases, one dominant deterioration process such as carbonation or chloride penetration is taken into consideration. Experimental results as well as observations in practice show that this is not a realistic and certainly not a conservative approach. In order to test more realistically, RILEM TC 246-TDC, founded in 2011, has developed a method to determine the durability of concrete exposed to the combined action of chloride penetration and mechanical load. In this report, a test method is presented which allows determination of realistic diffusion coefficients for chloride ions in concrete under compressive or tensile stress. Comparative test results from five different laboratories showed that the combination of mechanical and environmental loads may be much more severe than a single environmental load without mechanical loading. Modelling and probabilistic analysis also showed that the obvious synergetic effects cannot be neglected in realistic service life prediction

Julat rujukan bagi jumlah homosisteina dalam plasma di kalangan kanak-kanak di Malaysia

Homosisteinemia merupakan salah satu penyakit kepincangan metabolisme terwaris (IEM) yang menyebabkan peningkatan paras homosisteina. Homosisteina adalah salah satu asid amino mengandungi sulfur yang mempunyai kumpulan thiol yang dibentuk hasil daripada proses demetilasi asid amino methionina. Dalam penyakit kepincangan metabolisme terwaris (inborn errors of metabolism – IEM), terdapat tujuh jenis penyakit berpunca daripada kekurangan enzim yang terlibat dalam metabolisme homosisteina. Paras jumlah homosisteina adalah berbeza mengikut jenis penyakit akibat kekurangan enzim ini. Maka, terdapat keperluan bagi mewujudkan suatu julat rujukan untuk membezakan antara populasi normal dengan populasi berpenyakit. Kajian ini menerangkan penemuan berkenaan julat rujukan bagi jumlah homosisteina di kalangan kanak-kanak di Malaysia. Sebanyak 3 ml darah telah diambil daripada 86 individu normal (52 orang kanak-kanak lelaki dan 34 orang kanak-kanak perempuan) dan seterusnya diproses serta dianalisis menggunakan kaedah kromatografi cecair berprestasi tinggi jenis fasa penukar ion (HPLC-IEC). Hasil kajian mendapati min jumlah homosisteina bagi keseluruhan populasi rujukan ialah sebanyak 8.1 ± 3.89 μM (95% selang keyakinan 7.3-8.9 μM). Julat rujukan sedia ada bagi populasi rujukan adalah sebanyak 2.5 – 16.2 μM dengan had pemutus terendah (lower cut-off) dan had pemutus teratas (upper cut-off) masing-masing adalah 1.0 μM dan 21.0 μM. Julat tersebut didapati agak tinggi berbanding dengan penyelidik luar. Penemuan julat rujukan bagi jumlah homosisteina untuk populasi kanak-kanak di Malaysia yang terbaru ini dapat mengurangkan jumlah kadar positif palsu semasa proses diagnosis penyakit dilakukan

Bio-Based self-healing mortar

This paper investigates the effects of alkaliphilic spore-forming bacteria of the genus Bacillus on the compressive strength of the mortar cube and the healing capacity of the bacteria as healing agent on mortar containing crack. The experiments were carried out using cube test, stereomicroscopy and environmental scanning electron microscopy (ESEM). Cracked mortar specimen with and without the presence of the bacteria-healing agent were prepared. Results showed that the inclusion of these bio-healing agent in mortar mixtures cause more pore volume, which has no significant effect on compressive strength development at 28 days. In the series of healing capacity test, the cracks were significantly healed in bacteria-based than in control specimens after 28 days incubated in water bath and thus, increase permeability resistance of bacteria-based mortar specimens.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public. Part of the Special Issue: Civil EngineeringMaterials and Environmen