PENGARUH ABU VULKANIK SEBAGAI BAHAN STABILISASI TANAH UNTUK LAPIS SUBGRADE

Subgrade is the base ground surface or ground excavation or compacted filled surface soil and form a base surface for placement the section of other pavement. The strength and durability of pavement construction depends on the characteristic of soil bearing capacity. The better spec for the subgrade soil, the value of soil bearing capacity increasingly great. This study aims to evaluate how much influence the use of stabilization material (volcanic ash) with varying levels and constant mixture of lime on the soil samples to the value of consistency limits, dry volume weight- moisture content relation and review of the CBR value. The research was carried out by mixing native soil with lime stabilization material constantly weight percentage of 5% and volcanic ash that varied by 5%, 10%, 15%, 20%, 25% and 30% of the soil dry weight. To determine the maximum density and the value of CBR, researcher use standard proctor device and CBR testing laboratory and Atterberg limit testing to determine the limits of consistency. These tests concluded that the soil samples in the category of poor clay soil as subgrade material. After stabilized using volcanic ash and lime is seen that there is an increase in the carrying capacity of the power, that�s increasing the volume of dry weight, decreasing of soil swelling and increasing in the value of CBR. However, the CBR value that less than 5% of the soil mixture experiment results are categorized into the soil criteria with a low CBR value

METODE PELAKSANAAN PEKERJAAN CORE WALL PT. PEMBANGUNAN PROYEK APARTEMEN SKYLAND CITY ROSE IN SPRING JATINANGOR PP (PERSERO) Tbk. - CABANG IV

In the process, there are so many methods to maintain the stability of high rise buildings especially in resisting the lateral loads that have sigfinicant effects on it. Several systems are introduced to maintain the stability og high rise building including a shear wall structure and core wall. The core wall itself is a linear supporting wall system fits enough for high rise buildings in which have a fixed needs of functionality and utilities. The aims of final task writing are to find out about the work phase of the core wall implementation, to know the formwork method used in the implementation of the core wall�s works and also to understand the problems in the implementation process of the work. In practice, there are several stages in core wall�s work. Among of them are measurement jobs, scaffolding jobs, iron fabrication, formwork jobs, formwork inspections, concrete quality check, casting the core wall and dismantling the formwork. The formwork method used is the climbing method. Based on the information above, it can be concluded that the core wall has some advantages and disadvantages. Therefore, in the execution of the core wall�s works still need further inspection on each job carefully

PENGARUH WAKTU PEMERAMAN TERHADAP SIFAT FISIS DAN MEKANIS TANAH EKSPANSIF STABILISASI KAPUR MODIFIKASI ABU VULKANIK MERAPI

Clay soils have a high plasticity with a high degree of high shrinkage and low strenght. Many examples of damage arising from the nature of the expansive clay soils, such as a decrease in building foundations, crackes and waves on the highway structures, bridge abutments tilt, and others. Many things were done to improve the properties of expansive soils, like soil stabilization. Soil stabilization is a soil mixing with certain materials in order to improve the properties of the original soil. In this study, is used lime modified with Merapi volcano ash to improve the physical and mechanical properties as add material. Clay used in this study from Dusun Krebet, Kulon Progo Yogyakarta with a mixture of volcano ash trim variations of as much as 15%, 20% and 25% and 5% addition of lime for every variation of the dry weight of the soil mixture with curing time for 1, 3, 7 and 14 days. The tests were a test of physical and mechanical properties. The results show that for each variation of the mixture, the curing mixture of soil + volcano ash + limestone is influenced by the time. Shrinkage Limit, Plasticity Index (PI), and the permeability coefficient tends to decrease during 14th day. Meanwhile cohesion values decreased on 3rd day and then rise again with increasing curing aging time, so that the value of increased soil parameters was increased. Based on these results, it can be concluded that the longer the curing aging time on a mixture of clay, the better results will be obtained to improve soil properties

PENGARUH WAKTU PEMERAMAN TERHADAP SIFAT FISIS DAN MEKANIS TANAH EKSPANSIF STABILISASI KAPUR MODIFIKASI ABU VULKANIK KELUD

Expansive soils are fine-grained soil types that have a high plasticity index, low carrying capacity, and is sensitive to changes in water content so that the nature and development of shrink and swell. This is very disserve when expansive soil is used as a basic building construction. To overcome this stabilization needs to be done on the ground as a basic construction. This stabilization is utilizing on Kelud volcanic ash combined with lime. This study conducted by mixing soil stabilization material original to be three and four variations of curing time. A mixture of ash, respectively 15%, 20%, 25% and 5% lime to soil dry weight. For a long curing time used 1, 3, 7, and 14 days. The tests were the soil physical properties test and the soil mechanical properties test . The results of the research on native soil mixed with volcanic ash and lime showe that the addition of vulcano ash and curing time can degrade the soil plasticity index, the value of the permeability coefficient and mix soil cohesion, while the value of the shear angle increases. The soil physical properties is known the variation of 25% Kelud ash + 5% lime impaired greatest plasticity index with curing period of 14th days. On the permeability variation test 15% Kelud ash + 5% lime impaired greatest permeability coefficient with 14th days curing period. In soil shear strength test variations 25% Kelud ash + 5% lime increase the value of friction angle with 14th days curing time