Authors:Lucia Kidalova, Nadezda Stevulova, and Eva Terpakova
All composites based on natural fibers absorb moisture in humid atmosphere and when immersed in water or capillary action. Therefore, one of the major drawbacks of polymer fibers is their high availability to moisture sorption and their heterogeneity, which leads to a weak interface between the fibers and matrix and a poor transfer of the applied stress between the materials, resulting to reduction of physico-mechanical properties. An experimental investigation was conducted to testing the water absorption of hemp composites with MgO-cement binder and its influence on the physico-mechanical and thermal characteristics of composites. The achieved results of composites indicate that water absorption test has deteriorative influence on observed properties due to the degradation of the fibre-matrix interface.
Authors:Carlos Andrade, Ricardo Matos, Viviane Oliveira, Jussara Durães, and Maria Sales
X-ray diffractograms of the samples were obtained on a Rigaku Diffractometer Mod. Geiger FlexD/Max-2/C, Cu-K & , operating at 40 kV, 20 mA and at a rate of 1° min −1 .
The samples (2 cm 2
Sustainability and scarcity in resources are the two major issues to be dealt within the present scenario by effective utilization of alternative materials. In this present study, an attempt has been taken to study the effect of supplementary materials such as fly ash and silica fume as a partial replacement to cement and steel slag and M-sand as a replacement to river sand on strength and durability of concrete. In this study, concrete specimens were prepared based on five different mixes by varying the percentages of these supplementary materials. Various mechanical properties like compressive strength, split tensile strength and flexural strength were performed to ascertain the mix with optimum levels of replacement of supplementary materials for cement and fine aggregate. Durability property like water absorption test was performed on the mix with optimum values of strength. Results revealed that mix with higher percentages of steel slag, optimum level of silica fume and fly ash have shown higher strength and lesser permeability in concrete.
Self-compacting concrete has gained a wide range of applications as a result of its unique properties, which can offer high strength and durable type of concrete with the proper selection of the raw materials. The purpose of this study was to show the effect of the use of high dosage of air entraining admixture on the properties of self-compacting concrete. An experimental investigation on the frost-salt scaling resistance of conventional and air entraining selfcompacting concrete incorporating slag-blended cement and supplementary cementitious materials was carried out. Further fresh and hardened properties tests including slump flow, V-funnel, compressive strength, splitting tensile strength, air void characteristics and water absorption tests were performed to obtain an objective evaluation between air and non-air entrained self-compacting concrete mixtures. Air void characteristics were evaluated through the automated image analysis procedure to enrich this investigation. Results indicate the following: the air entraining admixture highly decreased the compressive strength up to 52% and the metakaolin was the governing supplementary cementitious material concerning the scaling resistance and water absorption in comparison with the silica fume.
Authors:SKM. Pothinathan, M. Muthukannan, N. Selvapalam, and S. Christopher Gnanaraj
continuously at a rate of 140 kg/cm 3 tile failure. 2.3.3 Waterabsorptiontest The waterabsorptiontest was conducted after 28 days of the curing period and the specimen was prepared according to IS 1199 [ 27 ]. In this test, an average of three specimens
Authors:K. S. Ajay Venkadesh, K. Harish Kumar, B. Hariharan, A. Arumugam, A. Nithish Kumar, P. Karthigai Priya, and S. Vanitha
properties, waterabsorptiontest, soundness test, hardness and impact tests are carried out. In waterabsorptiontest, the brick specimens are immersed in water for a period of 24 h and then the increase in weight is calculated. The weight should not be more