Achfas Zacoeb

Effect of fly ash on the strength of concrete made from recycled aggregate by pulsed power

The performance of concrete made from recycled aggregate that produced by pulsed power technology due to the use of fly ash has been studied. Pulsed power technology has been proven to reproduce high quality recycled aggregate. Concrete made from 100% recycled coarse aggregate by pulsed power discharge can reach similar compressive strength to natural coarse aggregate concrete. The use of JIS type II fly ash as cement replacement of 25% and 50% mass without adjustment of water to cement ratio can reduce the compressive strength of concrete. However, with the same fly ash percentage, in 28 day of age, concrete made from recycled aggregate by pulsed power technology results better strength by 10.0% and 15.8% compared to natural aggregate concrete for 25% and 50% of fly ash, respectively. In addition, mixing method using two-stage mixing approach (TSMA) has been applied to improve concrete strength. This method in making recycled aggregate concrete can improve the strength of fly ash concrete made from recycled aggregate concrete up to 4.7%. Replacing 25% of cement mass with fly ash for concrete made from recycled aggregate by pulsed power technology has shown preferable result in strength, and can be improved by using TSMA method in mixing process.

Experimental Study of Precast Walls with Variation Type of Opening Due to Vertical and Lateral Static load

The main existing research aim is to carry out an experimental investigation on three types of precast reinforcement walls. The First type of wall is with door opening, the second is wall with a window opening and the third one is solid wall. It is very important to understand the wall behavior in different types, which is known by conducting experimental tests, subsequently the objectives of this experiment is to study the behavior of precast wall in three types, wall capacity, strain behavior, stress in wall and deflection, then understand the effect of openings in the walls. In this experimental study, eighteen specimens of precast wall have been tested, six specimens for each type, three for vertical load and three for horizontal load. The size of specimens was 1000, 1000, and 50 mm. When the theoretical and experimental results have been compared in deflection, it was found that there is a correlation between the deflection and the opening size, where the opening size is increased the deflection increases; on the other hand the load capacity decreases when the opening size increases. In other words the stress is increased when the opening size is increased.

Development of Mix Design Method in Efforts to Increase Concrete Performance Using Portland Pozzolana Cement (PPC)

Earthquake disaster can cause infrastructure damage. Prevention of human casualties from disasters should do. Prevention efforts can do through improving the mechanical performance of building materials. To achieve high-performance concrete (HPC), usually used Ordinary Portland Cement (OPC). However, the most widely circulating cement types today are Portland Pozzolana Cement (PPC) or Portland Composite Cement (PCC). Therefore, the proportion of materials used in the HPC mix design needs to adjust to achieve the expected performance. This study aims to develop a concrete mix design method using PPC to fulfil the criteria of HPC. The study refers to the code/regulation of concrete mixtures that use OPC based on the results of laboratory testing. This research uses PPC material, gravel from Malang area, Lumajang sand, water, silica fume and superplasticizer of a polycarboxylate copolymer. The analyzed information includes the investigation results of aggregate properties, concrete mixed composition, water-binder ratio variation, specimen dimension, compressive strength and elasticity modulus of the specimen. The test results show that the concrete compressive strength achieves value between 25 MPa to 55 MPa. The mix design method that has developed can simplify the process of concrete mix design using PPC to achieve the certain desired performance of concrete.

Portable urban agriculture technology and soil nutrient drive app that support farmers profit.

A narrow land farmed urban Agriculture. It used for daily fresh vegetables and fruit for the housing community in urban areas. Portable Urban Agriculture Technology as a support facility to increase production of Urban Agriculture, the Greenhouse portable system could be built and transferred to a specific location is convenient, safe, fast, lightweight structural material (PVC 0.55mm Tarpaulin) so that the Urban Agricultural Products closer to residential consumers in urban. The impact was the price was cheaper but quality. The objective was to plan, build and test prototype Water inflated tent activity as a facility to strengthen Greenhouses strength, speed, effectiveness and comfort. Application method stages of the Cup or SDN on a former tin mining land, with Portable Urban Agriculture Technology support soil nutrient drive are as follows: first Reconstruction of the land in the form of land arrangement in accordance contours and irrigation channels that exist in the field is very important to support the success of the method SDN; second Management of top soil in the form of top soil enriched with organic material will support environmental compliance in the soil, especially for the growth and development of VAM hyphae and root system; third Soil Amendment to improve the physical and chemical properties of former mining land; fourth Activities vegetation of mined land with SDN method optimizes the achievement of the goals replanting of sustainable of native vegetation for erosion and runoff, repair and restoration of biodiversity, landscape aesthetics that will impact habitat improvement fauna, biodiversity, soil productivity and water quality. Tree plant species such as Acacia mangium, Acacia auriculiformis and Leucaena diversifolia microbes that have been infected with mycorrhizal fungi (VAM) will be very effective and support this effort. Vegetation activities with SDN method includes the following steps: first Seedling plants with VAM; second Preparation of arable land that supports the development of VAM in the soil; third Planting of the first cup with VAM; fourth Incubate 1 month; fifth Planting of the second cup with VAM; sixth 1 month incubation; and seventh The planting of the main crop.

Finite element modeling of bending failure at HPFRC plates using 2-dimensional isoparametric element

This paper presents finite element modeling of the bending failure on High-Performance Fiber-Reinforced Concrete (HPFRC) plate subjected to monotonic loading. Plate analysis is commonly used approach to plate bending theory. The results are sometimes less in accordance with laboratory tests. The aim of this study is to analyze the behavior of bending until failure which occurred at HPFRC plate, and load-displacement relation caused by variations of plate depth. Analysis carried out by 2-D isoparametric finite element method, with the approach of plane strain condition. The analysis was done by decreasing the stiffness of plate elements layer gradually in accordance with the development of maximum stress in the element due to workload. The rigidity of plate elements layer will be close to zero when maximum stress reaches a maximum tensile strength of HPFRC. Validation testing program conducted on plate specimen with a span length of 600u2005mm, width 300u2005mm and thickness variation of 40u2005mm, 50u2005mm and 60u2005mm. HP...