A Study on High Performance Fine-Grained Concrete Containing Rice Husk Ash

The objective of this work was finding out the most advisable testing conditions for an effective and robust characterization of the tensile strength (TS) of concrete disks. The independent variables were the loading geometry, the angle subtended by the contact area, disk diameter and thickness, maximum aggregate size, and the sample compression strength (CS). The effect of the independent variables was studied in a three groups of experiments using a factorial design with two levels and four factors. The likeliest location where failure beginning was calculated using the equations that account for the stress-strain field developed within the disk. The theoretical outcome shows that for failure beginning at the geometric center of the sample, it is necessary for the contact angle in the loading setup to be larger than or equal to a threshold value. Nevertheless, the measured indirect tensile strength must be adjusted to get a close estimate of the uniaxial TS of the material. The correction depends on the loading geometry, and we got their mathematical expression and cross-validated them with the reported in the literature. The experimental results show that a loading geometry with a curved contact area, uniform load distribution over the contact area, loads projected parallel to one another within the disk, and a contact angle bigger of 12°is the most advisable and robust setup for implementation of BT on concrete disks. This work provides a description of the BT carries on concrete disks and put forward a characterization technique to study costly samples of cement based material that have been enabled to display new and improved properties with nanomaterials.

Section: Introductionmentioning

confidence: 99%

Brazilian Test of Concrete Specimens Subjected to Different Loading Geometries: Review and New Insights

García

Márquez

Zúñiga-Suárez

et al. 2017

“…suitable for high performance construction materials (Constantinides et al 2003;Jeong et al 2015;Le et al 2014;Sriravindrarajah et al 2012;Divsholi et al 2014;Sorensen et al 2014). Based on the progress in concrete technology, high strength concrete (HSC) with compressive strength of 100 MPa or above has been developed and applied in various construction fields.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties and Modeling of Amorphous Metallic Fiber-Reinforced Concrete in Compression

Dinh

Kim

2016

The aim of this paper is to investigate the compressive behavior and characteristics of amorphous metallic fiberreinforced concrete (AMFRC). Compressive tests were carried out for two primary parameters: fiber volume fractions (V f ) of 0, 0.3, 0.6 and 0.8 %; and design compressive strengths of 27, 35, and 50 MPa at the age of 28 days. Test results indicated that the addition of amorphous metallic fibers in concrete mixture enhances the toughness, strain corresponding to peak stress, and Poisson's ratio at high stress level, while the compressive strength at the 28-th day is less affected and the modulus of elasticity is reduced. Based on the experimental results, prediction equations were proposed for the modulus of elasticity and strain at peak stress as functions of fiber volume fraction and concrete compressive strength. In addition, an analytical model representing the entire stress-strain relationship of AMFRC in compression was proposed and validated with test results for each concrete mix. The comparison showed that the proposed modeling approach can properly simulate the entire stress-strain relationship of AMFRC as well as the primary mechanical properties in compression including the modulus of elasticity and strain at peak stress.

“…With the presence of calcium hydroxide, or with other alkali hydroxides, it reacts to form silicate or aluminosilicate structure (Le et al 2014). Pozzolanic activity can be assessed by determining the amount of calcium hydroxide consumed by the pozzolanic reaction.…”

Section: Pozzolanic Activitymentioning

confidence: 99%

Evaluation of Pozzolanic Activity for Effective Utilization of Dredged Sea Soil

Moon

Kim

Lee

et al. 2017

In this work, pozzolanic activities of dredged sea soil from two different sources (South Harbor at Busan and Jangsaengpo Harbor at Ulsan) in Republic of Korea were investigated. Dredged sea soil used for this work has passed through a patented purification process, and particle size distribution, X-ray fluorescence, X-ray diffraction, and thermogravimetry/differential thermal analysis (TG/DTA) were utilized to understand its chemical and mineralogical characteristics. Temperature for heat treatment of dredged sea soil were determined using data obtained from TG/DTA, and pozzolanic activities of dredged sea soil samples were investigated by tracking the amount of calcium hydroxide spent for pozzolanic reaction as well as by monitoring the enhancement on 28 day compressive strength. According to the results, dredged sea soil samples from Jangsaengpo Harbor, which contains some amount of silt sized minerals, showed clear pozzolanic activity after heat treatment at 500°C. However, dredged sea soil samples from South Harbor did not exhibit strong pozzolanic reaction due to its larger particle size. At least, it was found that dredged sea soil samples have possibility to be used as a pozzolanic material after proper heat treatment if the size distribution of the particle contains certain amount of silt.