Abu kayu adalah produk hasil kesan daripada pembakaran kayu, kilang kertas dan pembakaran kayu jenis lain. Abu kayu ini berbentuk serbuk dan amorfus pepejal. Portland konkrit digantikan dengan 5, 10, 15, 20, 25 and 30 peratus daripada jumlah keseluruhan berat simen konkrit. Konkrit tanpa abu kayu (0% ) berfungsi sebagai kawalan. Nisbah campuran yang digunakan 1:2:4 dan nisbah air/konkrit dikekalkan pada 0.55 untuk setiap bancuhan konkrit. Rawatan stim dikenakan dalam tekanan suhu atmosfera kurang daripada 100°C dan optimum suhu rawatan stim berada dalam lingkungan 65°C hingga 80°C. Rawatan stim dilakukan selepas 3 jam penuangan konkrit untuk mengelakkan retakan mikro dan peningkatan liang pada struktur konkrit disebabkan oleh pengembangan terma pada konkrit tersebut. Rawatan pemanasan konkrit dijalankan selama 8 jam tanpa henti. Kitaran tempoh keseluruhan rawatan stim termasuk tempoh awalan pemanasan, pra-pemanasan dan penyejukan sample diaplikasi untuk projek ini. Empat jenis ujian ketahanan diaplikasikan seperti penembusan pesat klorida, kebolehtelapan gas , penyerapan air dan keliangan dan juga penembusan permukaan awal untuk menunjukkan ketahanan konkrit dalam suasana agresif. Keputusan menunjukkan simen Portland yang dicampur dengan abu kayu kurang menghasilkan kebolehkerjaan. Kesimpulannya, peningkatan tahap penggantian simen dengan abu kayu menyebabkan pengurangan kadar terhadap kebolehtelapan, penyerapan air peratusan dan keliangan, kadar resapan dan nilai kekonduksian pada hari ke - 7 dan ke - 28. Abu kayu mempunyai peratus kurang daripada 10% menunjukkan prestasi ketahanan yang baik.
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Wood Ash is by-product of combustion in wood power plants, paper mills and other wood burning facilities and it also renewable source of energy. The characteristics of this material are to be powdery and amorphous solid. Concrete mix is replaced by 5, 10, 15, 20, 25 and 30 % by weight of the cement in concrete. Concrete with no wood ash (0 %) serves as the control. The mix ratio used was 1:2:4 with water to binder ratio maintained at 0.55. Steam curing is generated in atmospheric pressure at temperature below 100°C and the minimum and maximum curing temperatures in range 40 to 100 °C. Various kind of temperature in curing will be affecting the result of the durability of concrete. However, the optimum curing temperature has been founded to be in range of 65°C to 80°C for 8 hours. The sample is cured after casting for 3 hours to avoid microcracking and porosity due to thermal expansion of fresh concrete. For period cycle of the steam curing, delay period pre-heating and cooling down period are applied. Percentage variation of wood ash and various steam curing temperatures are applied and four durability tests such as rapid chloride penetration, gas permeability, water absorption and porosity and also initial surface penetration are used to show the ability of concrete to the durability performance. The result shown the Portland cement blended with wood ash reduced the workability fresh concrete. As conclusion, increased level of cement replacement resulted in reduction of permeability rate, percentage water absorption and porosity, diffusion rate and conductivity value at normal curing at day 7 and 28. The percentage wood ash needs less than 10 % archived good durability performance.
Study on various steam curing regimes on the transportation properties of a normal concrete containing wood ash / Nur Hana Zakaria