CERS - 2014

Permanent URI for this collectionhttp://192.248.9.226/handle/123/17777

Browse

Browsing CERS - 2014 by Author "Dilrukshi, KGS"

Filter results by typing the first few letters
Now showing 1 - 3 of 3
  • Thumbnail Image
    item: Conference-Full-text
    Determination of suitability of the limestone aggregates as coarse aggregate for concrete
    (Department of Civil Engineering, University of Moratuwa, 2014-03) Perera, MUD; Dilrukshi, KGS; Hettiarachchi, MTP
    The use of limestone in the construction industry has been increasing due to its potential as aggregate. Some of the benefits of limestone include good strength, low possibility of alkali-silica reaction and the decrease in drying shrinkage in concrete. In the northern part of the Sri Lanka, limestone is used as aggregate in concrete due to its availability'. The aim of this research is to observe, evaluate, compare and discuss general characteristics of the limestone aggregate in the northern part of Sri Lanka and check the suitability of the limestone as coarse aggregates in concrete. There are two different kinds of limestone there, namely Red limestone and white limestone. Then experiments are conducted for both kinds of limestone together with the normal coarse aggregates. The properties of density, water absorption, particle size distribution, Flakiness Index, Los Angeles Abrasion Value, Aggregate Impact Value, Aggregate Crushing Value and Soundness of the aggregate are observed. The results are compared with the properties of the coarse aggregates and then suitability of limestone aggregates is evaluated.
  • Thumbnail Image
    item: Conference-Full-text
    Investigation of the properties of limestone concrete
    (Department of Civil Engineering, University of Moratuwa, 2014-03) Hemadasa, MBC; Dilrukshi, KGS; Hettiarachchi, MTP
    More than seventy percent of the volume of concrete is occupied by aggregates. AggreSates w^h undesirable qualities will have an adverse effect on durability and structural performance of concrete. Though gneiss is normally used as coarse aggregates in production of concrete, due to their unavailability in the region, limestone is used as coarse aggregate for production of concrete in Northern Sri Lanka, without appropriate investigations. In this study, impact of limestone aggregates on concrete properties such as slump, initial setting time compressive strength, flexural strength, etc. were investigated under laboratory conditions and the results were compared with the concrete made with normal aggregates. Two types of limestone aggregates were used for this purpose, red limestone which was collected from YValikamam west, Jaffna and white limestone, which was collected from Chavakachcheri area. Abstract: It was found that water absorption of limestone aggregates is 50% higher than that of the normal aggregates. Also, workability and compaction ability in limestone concrete are significantly lower for a given w/c ratio compared to normal aggregate concrete. However, compressive strength and flexural strength are found to be the same as the normal aggregates. Also, results indicate that red limestone aggregates have better performance than the white limestone aggregates.
  • Thumbnail Image
    item: Conference-Full-text
    Study of torsional buckling behavior of carbon nanotubes using molecular dynamics simulations
    (Department of Civil Engineering, University of Moratuwa, 2014-03) Dodangoda, MT; Dilrukshi, KGS; Hettiarachchi, MTP
    An accurate study of mechanical behavior of CNTs is vital to understand their response under mechanical loading in their applications. Much experimental and analytical work has been done to quantify the mechanical properties of CNTs over the past two decades. However, limited studies have been reported related to torsional behavior and estimation of shear modulus. The reported values of shear modulus of CNTs in the literature also shows considerable variations revealing the effects of the method used in the predictions. This paper reports the study carried out to investigate the effect of different parameters in estimating shear modulus and torsional buckling behavior of CNTs using molecular dynamic (MD) simulation method. MD simulator called largescale atomic/molecular massively parallel simulator (LAMMPS) is used in this regards. The effects of potential function (REBO and AIREBO) used to define atomic interaction and ratios of the CNT considered in simulation were studied with respect to Armchair and Zigzag CNTs with different diameters. The results of the studyrevealed that the effect of the CNT aspect ratio for estimating the shear modulus can be eliminated by using the CNTs with aspect ratio above 12. However, potential function use for the simulations has considerable impact on the results.