Rudy Djamaluddin

Mechanical behavior of the U-anchor of super-CFRP rod under tensile loading

A suitable anchoring system is required to anchor a CFRP tendon due to its sensitivity in lateral pressure. Recent developed anchors are still relying on lateral pressure in anchoring CFRP tendons. A new CFRP unit equipped with U-anchor at both end of the rod body without any jointing (namely of Super CFRP, S-CFRP) has been developed. This paper presents the mechanical behavior as well as failure mechanism of U-anchor under direct loading and loaded under embedded within concrete, respectively. The rupture occurred on the circular part of U-anchor under direct loading. The stress concentration on circular loop was the cause of U-anchor rupture. Loading of U-anchor embedded within concrete indicated an optimum capacity. The failure was out of the anchor system. Finite element model of U-anchor embedded within concrete showed better stress distribution on anchor at rupture load such that the stress on U-anchor was lower than CFRP strength.

Bond Characteristics of GFRP Sheet on Strengthened Concrete Beams due to Flexural Loading

Fiber reinforced polymer (FRP) has been applied to many purposes for civil engineering structures not only for new structures but also for strengthening of the deteriorated structures. The application of FRPs in various forms such as rod, grid and sheet are widely accepted solution due to its corrosion resistance as well as high tensile strength to weight ratio. Glass composed FRP (GFRP) sheet is most commonly used due to its relatively lower cost compared to the other FRP materials. GFRP sheet is applied externally by bonding it on the concrete surface. Many studies have been done to investigate the bonding of GFRP sheet. However, it is still very rarely studies on the bonding behavior of GFRP sheet on the strengthened beams due to flexural loadings. This is important to be clarified for the wider application of GFRP sheet especially on the flexural structure such as highway bridge girders. This study presented the results of experimental investigation of the bonding behavior on the strengthened concrete beams due to flexural loadings. A series of concrete beams strengthened with GFRP sheet on extreme tension surface were prepared. Results indicated the bonding distribution along the GFRP sheet due to flexural loading tended to be non-linear. The bond stress due to flexural loading was lower than the direct shear bond stress.

Corrosion of Concrete Using Portland Composite Cement and Rice Husk Ash under Simulated Acid Rain Environment

Cement production, which results in higher CO2 levels, has a negative impact on environment. This phenomenon has caused the emergence of a new type of environmentally friendly cement, such as Portland Composite Cement (PCC). On the other hand, rainfall becomes high acidity level. This will be an issue in the construction of concrete, which causes concrete deterioration if value of pH is below 6. The purpose of this study is to investigate corrosion caused by acid rainfall when used PCC cement mixed with RHA. RHA replacement level of 5%, by weight of cement was used in this study. The compressive strength design was 30 MPa. The simulated acid rain solution was prepared by mixing solution of H2SO4 and HNO3 to reach value pH of 4. The deterioration was measured by the number of corrosion product using SEM test. The results indicate a decrease in the number of component corrosion that occurs by using ASP.

Bonding capacity of the GFRP-S on strengthened RC beams after sea water immersion

Construction of concrete structures that located in extreme environments are such as coastal areas will result in decreased strength or even the damage of the structures. As well know, chloride contained in sea water is responsible for strength reduction or structure fail were hence maintenance and repairs on concrete structure urgently needed. One popular method of structural improvements which under investigation is to use the material Glass Fibre Reinforced Polymer which has one of the advantages such as corrosion resistance. This research will be conducted experimental studies to investigate the bonding capacity behavior of reinforced concrete beams with reinforcement GFRP-S immersed in sea water using immersion time of one month, three months, six months and twelve months. Test specimen consists of 12 pieces of reinforced concrete beams with dimensions (150x200x3000) mm that had been reinforced with GFRP-S in the area of bending, the beam without immersion (B0), immersion one month (B1), three months...

Flexural Capacity of Reinforced Concrete Beams Strengthened Using GFRP Sheet after Fatigue Loading for Sustainable Construction

Fiber reinforced polymer (FRP) has been applied not only for the simple structures but also for the advanced structures such as bridges or highway bridges for sustainable construction. In case of bridges or highway bridges, the structures experience not only static loadings but also fatigue loadings that may limited the serviceability of the bridge structures. In order to extend of the application of FRP on the such bridge structures to have a sustainable structures, the flexural capacity due to fatigue loading should be clarified. Glass composed FRP sheet namely Glass Fiber Reinforced Plastics (GFRP) is most commonly used due to its relatively lower cost compared to the other FRP materials. GFRP sheet is applied externally by bonding it on the concrete surface. Many studies have been done to investigate the flexural capacity of concrete beams strengthened using GFRP sheets. However, studies on the flexural capacity after fatigue loadings are still very rarely. This study presented the results of experimental investigation on the flexural capacity of the strengthened concrete beams after fatigue loadings. A series of concrete beams strengthened with GFRP sheet on extreme tension surface were prepared. Results indicated that after 800000 time of load cycle, the flexural capacity of beams specimens may decrease to only approximately 60%. The beam failed due to delaminating of GFRP sheet.

Ultimate Experiment of Ruptured Concrete Beams Strengthened Using GFRP-Sheet after Fatigue Loads

An experimental study has been carried out to investigate the structural behavior of beam which was strengthened by glass fiber reinforced polymer (GFRP-S). The Experimental was carried out to determine the effect of fatigue loads on flexural capacity of reinforced concrete beams. Each specimen was 6 m long with 300x500 mm rectangular cross section. Each specimen was treated with different loads. In this study using two different loads applied to the beam was static loads and fatigue loads. Static load was applied to the beam (B1) without GFRP reinforcement, a beam control. (A2) applied static load beam with GFRP reinforcement. Fatigue load applied to the beam reinforced with GFRP (B2) as well. For (A1) beam load was applied to the ultimate strength after reached 51.84 kN load, and then the concrete beams was strengthened with GFRP and fatigue loading until crushed. The result of this research showed that deflection under fatigue loads was higher than deflection of static loads. GFRP reinforcement showed an increase in the capacity of the test beam. The Increase of the power of static loading with GFRP reinforcement of 4.4%. The increase in the fatigue strength of 75 kN was 4.7%, the imposition 167.5 kN was 4.2%, and the imposition 260 kN was 2.9%.

Effect of Sea Water Submersion on GFRP-S Bonding Capacity of Reinforced Concrete Beam

An experimental investigation on laboratory simulation of reinforced concrete beams submerged in sea water was carried out. The research aimed to analyze the beam flexural behavior cause by submersion effect in the marine environment and simulation pool. Flexural testing was conducted by using two point loading up to beams ruptured. Total 18 reinforced concrete beams of 10 cm x 12 cm x 60 cm in dimension with GFRP-S bonded on the bottom side. Nine beams were submerged in the marine environment and 9 beams were submerged in the simulation pool. Exposure period is 1, 3 and 6 months after 28 days cured in fresh water. The result indicate that the ultimate load and bonding capacity of beam specimens submersed in the marine environment were relatively lower than the specimens submersed in simulation pool. Based on this experimental study, submerging of specimens in simulation pool (Pp ) could be used to predict specimens submersed in marine (Ps) by using equation