Various research and experiments in the field of concrete is done as an effort to improve the quality of concrete, One of them to improve the quality of concrete is added admixture type D-retarder. It is expected that the results of these experiments and experiments are able to answer the higher demands in the foundry implementation which sometimes takes a long time. The purpose of this study was to investigate the effect of Type D dosage admixture on moderate quality concrete fc30, the dose of this study was 0%, 0.35%, 0.75%, 1.10% of sementitious weight. The test used is a compressive strength to determine the quality of fc30 while setting time to find the initial time of sett. which is used as parameter parameter does not occur cold joint. The result showed that experiment 1 as the parameter that is design without admixture type D-VZ, dose 0,00%, compressive strength 28 days 33,13 Mpa, experiment 2 dose 0,35%, compressive strength up 10% from experiment 1, 3 dose experiments 0.75%, a compressive strength rose 6% from experiment 1, experiments 4 doses 1.10%, a compressive strength down 4% from experiment 1. As for the D-VZ admixture dosage and addition dose, concrete deceleration deceleration, D-VZ type non-admixture concrete parameter, 1 dose 0,00% experiment resulted in initial sett 127 minutes, 2 dose experiment 0.35%, resulted in initial sett 267 minutes , experiment 3 dose 0.75%, resulted in initial sett 933 minutes, experiment 4 dose 1.10%, resulted in initial sett 2520 minutes. Expected from this research, can be used as a reference for Project Supervisor, Contractor, Readymix Supplier, especially for concrete over dose (= long concrete setting), which can be maintained with the reference of strong compressive strength achieved, so that the concrete loong setting on the structure is not in Demolish (= slash). And will be used as a handle if it requires deceleration concrete can be added admixture type D.
This paper presents an evaluation of probabilistic slope stability due to updating of Indonesia seismic hazard maps from 2010 to 2017 edition. The evaluation is conducted by presenting case study to compare the probability of failure of slope which subjected to seismic load determined from those seismic hazard maps. At first, simple slope models are built and the horizontal seismic coefficients are selected. Then, the probabilistic slope stability analysis is conducted using Monte Carlo simulation in LEM-based software so called Rocscience Slide 6.0. The simulation results indicate that the revision of Indonesia seismic hazard maps causes increasing of probability of failure of slope in the study area. These results show that the slope models become more prone to failure subjected to seismic load obtained from the seismic hazard maps.
Being located on the Pacific Ring of Fire, Indonesia has to cope with the constant risk of earthquakes which often trigger landslides in mountainous area, causing significant and even catastrophic damage. This paper presents probabilistic stability and sensitivity analysis of rock slope subjected to seismic loading based on Generalized Hoek-Brown failure criterion. Two approaches namely Limit Equilibrium Method (LEM) and Finite Element Method (FEM) were utilized using computer programs of Rocscience Slide and Phase2, respectively. The Generalized Hoek-Brown parameters such as, σci, GSI and mi were distributed normally with their coefficients of variation (COV) of 0.25, 0.125 and 0.1, respectively. The different seismic loadings expressed as Kh of 0.1, 0.3, and 0.5 were then subjected to the rock slopes and the probability of failure (Pf) was evaluated for each slope. Eventually, the results of Pf obtaining from LEM and FEM were compared and the most decisive parameter in slope stability were evaluated in sensitivity analysis. Based on the presented results of the analysis, the probability of failure (Pf) of the rock slopes which are subjected to the seismic loading generated by both FEM and LEM will decrease as the mean of GSI, σci, and mi increase. Moreover, the increment of the D value and seismic loading will induce the probability of failure (Pf) of the rock slopes which are generated by both FEM and LEM increase.
Revision of Indonesia seismic hazard maps would cause several changes in construction planning. In Pamekasan regency, there was an increasing in seismic load from maps of 2010 (kh=0,18) to 2017 (kh=0,22). So, it was necessary to be evaluated. Slope conditions with large loads and steep slopes can cause landslides so that slope reinforcement is needed. One of them is by using geotextile. This study aims to calculate the safety factor of slope (internal and external) with the influence of ratio between geotextile length and slope height (L/H) and vertical spasing of geotextile (Sv) which was done by using two calculations, namely manual calculation and Rocscience Slide 6.0 program. The results of the analysis show the decreasing of safety factor (SF) for unreinforced slope due to changes in the 2010 to 2017 seismic load of 5.263% calculated using Slide 6.0. Internal stability of pullout and rupture shows the decreasing of SF about 15,789%. External stability against sliding shows the decreasing of SF about 17,4% to 20,5%. External stability against overturning shows the decreasing of SF about 12,3% to 14,00%. External stability against bearing capacity failure shows the decreasing of SF about 35,2% to 36,6%. Global stability shows the decreasing of SF abou5,6% sampai dengan 6,4%.
Concrete is a building material that is very popularly used in the world of construction services, along with the rapid development of concrete technology has been successfully developed various innovation on additive material in concrete mixes to get good quality concrete. Consol SG is an additive material or admixture which is a product of liquid concrete plasticizers and high water reducing agents by regulating the effect of retarding, can increase workability without increasin g water content, reducing water without losing workability, and increasing compressive strength, and chloride free with no damaging on reinforcement. This research used an experimental method in a laboratory with a total of 60 samples of specimens, concrete compressive strength at 28 days with a cylinder diameter of 150 mm high by 300 mm with a variation of Consol SG mixture of 0%, 0.2% and 0.3% with high quality planned f'c = 30 MPa, on the effect of Consol SG addition on the compressive strength of the concrete which is viewed from the variation of Consol SG mixture. The results of the concrete compressive strength value of Consol SG 0.2% is 31.13 MPa (up to 2.54% in terms of normal concrete), for the variation of Consol SG 0.3% mixture of 32.25 MPa (up to 6.22% in terms of normal concrete). While the variation of 0.2% to 0.3% increased by (3.59%). The test of the statistical model used is the Chi-Square test and the T-test using the SPSS software.
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