Heru Purnomo

Tensile Characteristics of Coconut Fibers Reinforced Mortar Composites

Natural fibers such as coconut fibers are numerous in Indonesia. The tensile strength of coconut fibers produced in this country is among the highest of natural fibers ones. This paper is to determine the tensile strength of coconut fibers with or without special treatment (water washing dry) and assessment the ability of coconut fiber for reinforcement in mortar composites. Experimental observations on coconut fibers and mortars carried out. There were tensile tests and scanning electron microscopy (SEM) providing microstructural properties of coconut fibers. The results showed that the coconut fibers treatment increases tensile strength and provides higher failure strain values. It showed that coconut fibers largely improved tensile strength behavior of mortar composites. To a conclusion, the coconut fibers are able to be used as reinforcement for ductile mortar composites.

Effect of Fibers Content on the Tensile Properties of Coconut Fibers Reinforced Cement Mortar Composites

The coconut fiber presents higher ductile properties than other natural fibers. In previous studies, it demonstrated than Indonesian coconut fibers presents an improved tensile strength and failure strain after washed with water and dried. The coconut fibers have the potential to reinforce material for construction, especially in earthquake areas such as tropical countries. The purpose of this research is to assess the benefit brought by coconut fibers content on the tensile behavior of mortar composite. Splitting tensile strengths were measured and microstructure observed using scanning electron microscopy (SEM). The influence of fiber content (expressed by a mass ratio fiber/cement) is investigated. The results show that a fiber content of 5% allows a 10 times higher deflection and presents a 1.5 times higher tensile strength than mortar without fiber. Further studies will focus on the bond strength between the fiber and the cement mortar matrix.

Numerical Modelling and Simulation of Ferro Casting Ductile Shear Keys for Precast Concrete Girders

This paper discusses the numerical modelling and simulation of Ferro casting ductile (FCD) metal shear key, or connector, without epoxy used for joining segmental precast concrete girders. In contrast to other types of cast iron, FCD metals exhibit higher level of ductility. In an effort to identify an optimum shape of an FCD metal shear key the numerical study in this paper investigates the response of four different geometries of full scale FCD metal shear key to shearing force from the concrete members and prestressing force acting in the centreline of the connector. Nonlinear finite element analysis of the shear key and the adjoining concrete members are conducted using ANSYS academic package. The appropriate constitutive relations for the FCD metal and concrete materials are obtained from test results and published values in the literature. The study considers two different magnitudes of prestressing force and two different concrete compressive strengths. Numerical results indicate that introducing a taper onto the forward ring plate of the male part of the shear key results in a significant increase in its load-bearing capacity.

Influence of Water Content of Soil to Strength of Unfired Soil Lime Bricks

The paper discusses strength-time relation of unfired soil-lime bricks in presence of different water content of soil as one of principal materials for the brick making. Two batches of soil-lime bricks were made with a mixture of lime, soil and water with a mass proportion of 1: 5.7: 1. Water contents of the first and second batch of soil are 30% and 40.581% respectively. Both batches of brick underwent compression and three point bending test. Absorption and physical change of bricks were also evaluated. Experimental investigation reveals that for both batches of bricks, up to 90 days compressive strength decreases a little but modulus of rupture rapidly decreases with time. The study shows that unfired soil-lime bricks with lower soil water content resulted in better strength performances compared to those with higher soil water content.

Effect of Coconut Coir Uniformity on Strength of Unfired Soil Lime Bricks

The paper discusses strength-time relation of unfired bricks reinforced with and without natural fibers. Untreated and treated coconut fibers with three different lengths (1 cm, 2.5 cm and 4 cm) were prepared for soil lime bricks reinforcements. The effects of 4% uniform 2.5 cm fiber reinforcement was compared to the effects of 4% non-uniform fiber reinforcement, which constitutes a fiber mix between 1/3 part each of 1 cm, 2.5 cm and 4 cm fiber length. Absorption of brick was also evaluated. Experimental investigations reveal that for all type of bricks, up to 90 days compressive strengths decrease a little but bending strengths rapidly decrease with time. The results show that unfired bricks added with uniform treated fiber resulted in better strength performances compared to those added with uniform untreated, non-uniform untreated and non-uniform treated fibers, and also to those without fibers.

Effect of Coconut Fibers Addition to early Age Unfired Soil Lime Bricks Strength

Low rise buildings and rural houses in Indonesia are often constructed with non-standard bricks. In some provinces, like West Java, fired clay and unfired soil lime bricks co-exist as non standard bricks. These bricks are traditionally produced in home run plants with little adherance to appropriate mix designs. These unfired soil lime bricks enter the market within 2 weeks of production, which inflicts potential loss to the buyers due to their low performance quality. The paper discusses strength improvements of these early age unfired bricks by adding natural fibers. Untreated coconut fibers with three different lengths (1 cm, 2.5 cm and 4 cm) were prepared for bricks reinforcements. The effects of 2%, 4% and 6% fiber addition to the strength of bricks were investigated. The bricks reinforced with 4% fiber content resulted in better strengths compared to those reinforced with other percentage of fibers. The effect of fiber length uniformity to the bricks strength was also evaluated. A 4% non-uniform fiber addition, which constitutes 1/3 part each of 1 cm, 2.5 cm and 4 cm average fiber length, was investigated. The results show that unfired bricks added with uniform fiber resulted in better performances compared to those added with non-uniform fibers. Higher compressive and bending strengths, compared to those strengths of unfired plain soil lime bricks and traditional soil lime bricks, could be achieved through fiber addition.

Effect of Age on Strength of Unfired Soil Lime Bricks Containing Non Uniform Coconut Fibers

In some provinces in Indonesia, like West Java, fired clay and unfired soil lime bricks co-exist as non standard bricks. Low rise buildings and rural houses in Indonesia are often constructed with non-standard bricks. The paper discusses strength-time relation of unfired bricks reinforced with and without natural fibers. Untreated and treated coconut fibers with three different lengths (1 cm, 2.5 cm and 4 cm) were prepared for bricks reinforcements. The effects of 4% non-uniform fiber addition, which constitutes 1/3 part each of 1 cm, 2.5 cm and 4 cm average fiber length, was investigated. Absorption of the bricks was evaluated. For all type of bricks, up to 90 days compressive strengths are almost stable but bending strengths rapidly decrease with time. The results show that unfired bricks added with treated fiber resulted in better performances compared to those added with untreated fibers and without fibers.

Strength Improvement of Early Age Unfired Soil Lime Bricks

Despite their low performance quality and aesthetics, non-standard bricks are commonly used in the construction of low-rise buildings and rural houses in Indonesia. These bricks are produced traditionnally in home run plants with little adherance to appropriate mix designs. These unfired soil lime bricks enter the market within 2 weeks of production, which inflicts potential loss to the buyers due to their low performance quality. The paper discusses strength improvements of these early age bricks through 2 methods. The first method is by adding the optimal amount of mixing water to the soil and lime mix. The second method is by adding untreated coconut fibers with a 2.5 cm fiber length as additional reinforcements. The effect of 3%, 5% and 7% fiber addition to the mechanical properties of bricks were investigated. Laboratory tests showed that higher compressive strengths, compared to that of traditional unfired soil lime bricks, could be achieved through the 2 proposed methods. The bricks reinforced with higher percentage of untreated coconut fibers have better modulus of ruptures.