Effects of nano-silica on the gas permeability, durability and mechanical properties of high-strength lightweight concrete

2017 ◽  
Vol 147 ◽  
pp. 17-26 ◽  
Author(s):  
Nihat Atmaca ◽  
Mohammed Layth Abbas ◽  
Adem Atmaca
2019 ◽  
Vol 945 ◽  
pp. 188-192 ◽  
Author(s):  
A.A. Pykin ◽  
E.Y. Gornostaeva ◽  
N.P. Lukutsova ◽  
J.S. Pykina

The physical and mechanical properties of lightweight constructional heat-insulating concrete (sawdust gypsum concrete) with high-strength gypsum binder, modified by food cotton microcrystalline cellulose and organic fillers of plant origin from the waste wood of coniferous and deciduous species in the form of cavitationly processed pine and birch sawdust have been studied. The dependence of the cavitation extraction time of water-soluble reducing substances (sugars) from sawdust on the strength of sawdust gypsum concrete is established. The changes in microstructure of the gypsum matrix, the mean density, bending tension strength and compression strength, the thermal conductivity coefficient of sawdust gypsum concrete on the basis of the cavitationly processed sawdust with the introduction of microcrystalline cellulose are analyzed. It is proven that microcrystalline cellulose compacts the space between the crystalline hydrates of calcium sulfate dihydrate in the gypsum matrix microstructure and improves the physical and mechanical properties of sawdust gypsum concrete.


2015 ◽  
Vol 49 (4) ◽  
pp. 1221-1233 ◽  
Author(s):  
Ming Kun Yew ◽  
Hilmi Bin Mahmud ◽  
Payam Shafigh ◽  
Bee Chin Ang ◽  
Ming Chian Yew

2011 ◽  
Vol 374-377 ◽  
pp. 1499-1506
Author(s):  
Rong Hui Zhang ◽  
Jian Li

In this study, the effect of micro-expansion high strength grouting material (EGM) and Modified polypropylene coarse fiber (M-PP fiber) on the mechanical properties of lightweight concrete are investigated. The influence of EGM and M-PP fiber on compressive strength , flexural strength and drying shrinkage of concrete are researched, and flexural fracture toughness are calculated. Test results show that the effect of EGM and M-PP fiber volume fraction (Vf) on flexural strength and fracture toughness is extremely prominent, compressive strength is only slightly enhanced, and the rate of shrinkage is obviously decreased. It is observed that the shape of the descending branch of load-deflection and the ascending branch of shrinkage-age tends towards gently with the increase of Vf. And M-PP fiber reinforced lightweight aggregate concrete is more economical.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Ming Kun Yew ◽  
Hilmi Bin Mahmud ◽  
Bee Chin Ang ◽  
Ming Chian Yew

This paper presents the effects of low volume fraction(Vf)of polyvinyl alcohol (PVA) fibers on the mechanical properties of oil palm shell (OPS) high strength lightweight concrete mixtures. The slump, density, compressive strength, splitting tensile strength, flexural strength, and modulus of elasticity under various curing conditions have been measured and evaluated. The results indicate that an increase in PVA fibers decreases the workability of the concrete and decreases the density slightly. The 28-day compressive strength of oil palm shell fiber-reinforced concrete (OPSFRC) high strength lightweight concrete (HSLWC) subject to continuous moist curing was within the range of 43–49 MPa. The average modulus of elasticity (E) value is found to be 16.1 GPa for all mixes, which is higher than that reported in previous studies and is within the range of normal weight concrete. Hence, the findings of this study revealed that the PVA fibers can be used as an alternative material to enhance the properties of OPS HSLWC for building and construction applications.


Author(s):  
Omnia Saad ◽  
◽  
Khaled S. Ragab ◽  
Omar Elnawawy ◽  
Yousef R. Alharbi ◽  
...  

Using of Lightweight concrete (LWC) amounts to a lower cost and a better thermal performance due to its unique properties and light density. The main disadvantage in using lightweight concrete is that its mechanical properties are relatively poor. An effective method to improve the mechanical properties of lightweight concrete is using a dosage of nano-silica in the concrete mix. The gained enhancement of mechanical properties promotes a more serious discussion of structural applications of lightweight concrete. There exists an optimum dosage of nano-silica by which the mechanical properties enhancement is maximized. Increasing the nano-silica content beyond the optimum dosage degrades the mechanical properties. However, a fixed optimum dosage is not agreed upon in literature. This paper investigates the optimum dosage of NS to enhance the mechanical properties and microstructure of a lightweight concrete made with lightweight expanded clay aggregates (LECA). The results concluded that a dosage of 0.75% of nano-silica is optimum for the studied lightweight concrete mixes.


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