Effects of Steel and Polypropylene Fiber Addition on Interface Bond Strength between Normal Concrete Substrate andSelf-Compacting Concrete Topping

Based on facts that the composite action in semi-precast and strengthened structural system depends on the bond strength of the interface between concrete faces of different ages, this preliminary research is aimed to investigate effects of mixed polypropylene (PPF) and steel fiber (SF) addition on the hardened properties of Self-Compacting Concrete (SCC) and its bond strength when used as topping layer on normal concrete substrate. Effects of hybrid fiber addition on the hardened properties of SCC were investigated based on the compressive, splitting tensile and flexural strength of concrete specimens which is tested in 28 days of age. In the next step, the tensile and shear strength of the interface were evaluated using indirect splitting tensile and bi-surface shear test method. In this research, fiber addition were prepared using 1 kg/m PPF and various SF addition ranging from 15 kg/m3, 20 kg/m3, 25 kg/m3 and 30 kg/m3. Test results indicate that hybrid fiber addition does not affect the compressive strength significantly but it leads ositive improvement to the splitting tensile and flexural strength of hardened SCC and also improve the bond strength between SCC and normal concrete. Hybrid fiber addition of 1 kg/m3 PPF which is combined with 20 kg/m3 SF can be suggested as optimum composition for Hybrid Fiber Reinforced Self-Compacting Concrete (HyFRSCC) that will be used as topping or overlay material based on its hardened properties and interface strength

The Aplication of Local Cane Sugar As A Retarding Admixture

Retarding admixtures or retardes are used in the mixing concrete to prolong the setting time or the plasticity of fresh concrete. This is normally done to avoid complications when unavoidable delay may occur between mixing and placing. Moreover, prolonging the setting time or the plasticity of fresh concrete is benefit in placing mass concrete or when the weather is quite hot that normally occurs in Indonesia. A retarder is also used to avoid a cold joint between previously poured concrete that is already hardened and new fresh concrete. This paper reports the effect of cane sugar on the setting time of cement paste using the standard Vicat apparatus to see how effective is the sugar cane can be used as a retarding ctchnixure. In the experiment cement paste was blended with various amount of cane sugar produced by Madukismo, Yogyakarta, Indonesia. The amount of cane sugar varies from 0 % to 0.20 % of the used cement in weight. The test results showed that cane sugar can be used as a retarding admixture. This is because the use of the cane sugar caused the delay of the setting time. For the various amount of sugar ranging from 0 % to 0.20 %, the setting time was increased from 2 hours to almost 18 hours

Determination of k for rigid pavement with cakar ayam system using heavy weight deflectometer (case study : Soekarno-Hatta Airport)

ABSTRAK One of the important parameter in determining the Aircraft Classification Number/Paement Classification Number (ACN/PCN) of rigid payement is the modulus of subgrade reaction (k). The current popular way to find the site modulus of subgrade reaction under the rigid pavement is by using the non destructive test with HWD (Heavy Weight Deflectometer). However the program nused to analyzedanalyze the collected data from the site is 0111y applicable for cOllventiol1al rigid pcn\u27emellt. This paper disclI.ue.f the necessary step-by-step procedure to apply the HWD using its accompanied program called ELMOD4 to calculate k ill the study of Soekamo-Hatta Airport, where the rigid pavement uses Cakar Ayam system. From thl\u27 .fwdy it i.\u27 .mggested that the k value of the .mbgrade i.f /5 MNlmJ. Therefore the suhgrade category of the Soekamo. Hattll Airport is D according to the ACNIPCN method Keywords: Pavement, sistem cakar aya

Dietermination of k for rigid pavement with cakar ayam system using heavy weight deflectometer (case study : Soekarno-Hatta Airport)

One of the important parameter in determining the Aircraft Classification Number/Paement Classification Number (ACN/PCN) of rigid payement is the modulus of subgrade reaction (k). The current popular way to find the site modulus of subgrade reaction under the rigid pavement is by using the non destructive test with HWD (Heavy Weight Deflectometer). However the program nused to analyzed analyze the collected data from the site is only applicable for conventional rigid pavement. This paper discuse of the necessary step-by-step procedure to apply the HWD using its accompanied program called ELMOD4 to calculate k ill the study of Soekamo-Hatta Airport, where the rigid pavement uses Cakar Ayam system. From thl\u27 .fwdy it i.\u27 .mggested that the k value of the .mbgrade i.f /5 MNlmJ. Therefore the suhgrade category of the Soekamo. Hatta Airport is D according to the ACNIPCN metho