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"It is widely use ofair-conditioning systems in Thailand due to its location. It is located in atropical zone with relatively high temperatures all year round, with highhumidity and high intensity of sunlight. In order to save electrical energy forair-conditioning systems, preventing heat transfer into the building isrequired. The objective of this study is to investigate the physical andthermal properties of concrete blocks. An attempt is made to increase heatresistance of concrete blocks. Foam beads (0-0.30% by weight) and kaolin (0-70% by weight) wereadded in concrete block mixture to increase discontinuous voids in concrete.Compressive strength and water absorption of concrete blocks were tested. Thetesting results indicated that compressive strength decreased when foam beadsand kaolin were added. Water absorption increased when foam beads were added.In contrast, the more kaolin added the less water absorption. The thermalconductivity coefficient of concrete blocks was also investigated. The resultsconfirmed that the higher the amount of foam beads or kaolin added, the higherthe thermal resistance of concrete blocks. Thermal time-lag behavior was alsoinvestigated. The results indicated that concrete block with kaolin took thelongest time in heating and took the shortest time in cooling. These propertiesare good for heat prevention in hot climate regions. These concrete blockswhich were developed and tested in this research conform to the Thai IndustrialStandard. Finally, it can be concluded that because of its thermal behavior,concrete block with kaolin is a suitable energy-saving concrete block for hotand humid climates."

"It is widely use of air-conditioning systems in Thailand due to its location. It is located in a tropical zone with relatively high temperatures all year round, with high humidity and high intensity of sunlight. In order to save electrical energy for air-conditioning systems, preventing heat transfer into the building is required. The objective of this study is to investigate the physical and thermal properties of concrete blocks. An attempt is made to increase heat resistance of concrete blocks. Foam beads (0−0.30% by weight) and kaolin (0−70% by weight) were added in concrete block mixture to increase discontinuous voids in concrete. Compressive strength and water absorption of concrete blocks were tested. The testing results indicated that compressive strength decreased when foam beads and kaolin were added. Water absorption increased when foam beads were added. In contrast, the more kaolin added the less water absorption. The thermal conductivity coefficient of concrete blocks was also investigated. The results confirmed that the higher the amount of foam beads or kaolin added, the higher the thermal resistance of concrete blocks. Thermal time-lag behavior was also investigated. The results indicated that concrete block with kaolin took the longest time in heating and took the shortest time in cooling. These properties are good for heat prevention in hot climate regions. These concrete blocks which were developed and tested in this research conform to the Thai Industrial Standard. Finally, it can be concluded that because of its thermal behavior, concrete block with kaolin is a suitable energy-saving concrete block for hot and humid climates."

"Pada suatu konstruksi bangnman, beton merupakan bagian yang penting danmempunyai andil yang besar terhadap kekuatan konstruksi bangunan tersebut. Salahsatu faktor yang mempengaruhi kekuatan beton ialah mutu material-material penyusuncampuran beton. Pada suatu bangunan tertentu diperlukan beton bertulang danpemasangan tulangan daiam beton bertulang ini harus sesuai dengan perhitungan yangtelah dilakukan ahli-ahli Sipil. Spesifikasi mutu beton biasanya dinyatakan dalam kuatcampuran beton. Untuk mengetahui apakah beton-beton yang ada pada suatu konstruksibangunan telah memenuhi spesifikasi yang diharuskan, tentunya perlu dilakukan suatupemeriksaanPemeriksaan ini dapat dilakukan tanpa merusak sehingga tidak mempengaruhikekuatannya setelah pemeriksaan dilakukan. Salah satu metoda tak merusak yang dapatdilakukan untuk pemeriksaan beton bertulang ini adalah uji ultrasonik, yaitu denganmemanfaatkan gelombang akustik berfrekuensi tinggi. Dasar dari metoda ini adalahadanya perbedaan kecepatan gelombang ultrasonik di dalam beton akibat adanya cacat-cacat berupa keropos atau retakan yang mungkin terdapat baik di dalam maupun padapermukaan beton dan adanya perbedaan kecepatan gelombang ultrasonik di dalamtulangan baja.Pada penelitian ini dibuat beberapa benda uji baik yang berbenruk kubus,silinder, maupun balok dengan maupun tanpa tulangan baja dengan kual lekan yangberbeda-beda sebagai model pengujian dengan pengkombinasian gradasi agreat kasar.Peugujian ultrasonik pada benda uji dilakukan dengan metode transmisi. Pada pengujian ini digunakan slat yang dapar mengeluarkan gelombang ultrasonik dengn frekuensi 54 khz dan kecepatan gelombang yang merambat dalam beton 3,5 - 4,5 km/s tergantung mutu beton."