Effect of Air Entertainment Using Olive Oil on Properties of Concrete

Air entrained concrete can be produced by introducing suitable air-entraining agent, one such commonly available material in India is Olive Oil which is being used in my experimental work. The primary objective of this study to find the appropriate amount of Olive Oil for strength and density, water absorption, other properties of concrete. For which the amount of Olive oil is varied from 0 %, 2%, 4%, and 6% Olive Oil by weight of 100 kg of cement. The test which was carried out in the experimental work were density, workability, strength, water absorption, the slump of air-entrained concrete. Total 48 No. of the concrete cube was cast for the experimental work. The result of the experiment work shows if Olive Oil is used in the range of 5-6% it will provide better workability, less water absorption with acceptable 5-7% decrease in compressive strength.

THE BOND STRENGTH OF STEEL BAR BASE ON RIB GEOMETRY BAR IN PULLOUT TEST

This experiment's objective is to prove that the reinforcing rib's form contributes to its bond strength. The specimen is the concrete cubes measuring 150 × 150 × 150 mm; bar installed in the center of the concrete cube. Bars use 13, 16, and 19 mm diameters. For comparison, the experiment was also carried out on plain reinforcement diameter with 12 mm, 16 mm, and 19 mm. Concrete compression is fc' 34 MPa. The pullout test was also performed to increase the load in stages at a 200 kg/minute speed. Loading stopped if the reinforcement yielded, split concrete, or slipped bar. The experiment uses ASTM standards ASTM C234-91a. The study results are the bond strength on reinforcement with the surrounding concrete. Bond strength in the plain bar is lower than deformed. The reinforcement of steep rib compared to fishbone bond strength values incline to be the same. The ratio of the bond strength of plain compared to deformed is 15% - 18%. The bond index of the steep rib and fishbone rib between 0.11 - 0.16 so that the bond stress obtained is also relatively the same. The failure pattern that occurs is determined based on the bond stress-slip graph. There are two types of collapse in this experiment, namely pullout and splitting damage. The failure of each specimen based on the diameter and shape of the rib varies greatly. The splitting damage is seen visually only in the specimen of the D19 fishbone rib.

Concrete Compression Test Data Estimation Based on a Wavelet Neural Network Model

Firstly, a genetic algorithm (GA) and simulated annealing (SA) optimized fuzzy c-means clustering algorithm (FCM) was proposed in this paper, which was developed to allow for a clustering analysis of the massive concrete cube specimen compression test data. Then, using an optimized error correction time series estimation method based on the wavelet neural network (WNN), a concrete cube specimen compressive strength test data estimation model was constructed. Taking the results of cluster analysis as data samples, the short-term accurate estimation of concrete quality was carried out. It was found that the mean absolute percentage error, e1, and the root mean square error, e2, for the samples were 6.03385% and 3.3682KN, indicating that the proposed method had higher estimation accuracy and was suitable for concrete compressive test data short-term quality estimations.

Strength and Durability Study of Concrete Structures Using Aramid-Fiber-Reinforced Polymer

Fiber-reinforced polymer (FRP) is an important material used for strengthening and retrofitting of reinforced concrete structures. Commonly used fibers are glass, carbon, and aramid fibers. The durability of structures can be extended by selecting an appropriate method of strengthening. FRP wrapping is one of the easiest methods for repair, retrofit, and maintenance of structural elements. Deterioration of structures may be due to moisture content, salt water, or contact with alkali solutions. Using FRP, additional strength can be gained by structural elements. This paper investigates the durability of aramid-fiber-wrapped concrete cube specimens subjected to acid attack and temperature rise. The study focuses on the durability of aramid-fiber-wrapped concrete by considering the compressive strength parameter of the concrete cube. Concrete cubes are prepared as specimens with a double wrapping of aramid fibers. Diluted hydrochloric acid solution is used for immersion of specimens for curing periods of 7, 30, and 70 days. The aramid-fiber wrapping reduces weight loss by 40% and improves compressive strength by 140%. In a fire resistance test, the specimens were kept in a hot air oven at a temperature of 200 °C at different time intervals. Even after fire attack, weight loss in specimens reduced by 60%, with about 150% enhancement in compressive strength due to aramid fiber.

The method of strengthening the church building in terms of the planned mining exploitation

This article describes the method of strengthening a church building in Ruda Śląska against predicted effects of mining exploitation. The building had been already exposed to effects of 22 mining incidents which significantly damaged walls and vaults. Therefore, it was decided to strengthen the building before new exploitation works. Strengthening works included longitudinal walls support with the tendon system built over the vault support. Additionally, ribs were strengthened by suspending them to new reinforced concrete ribs placed over the existing ones. And precast concrete cube elements were used in new ribs.