Effect of natural lightweight aggregate on fresh state properties of lime mortars

2021 ◽  
Author(s):  
Tomáš Žižlavský ◽  
Martin Vyšvařil
Keyword(s):  
Lightweight Aggregate ◽  
Lime Mortars ◽  
Fresh State

scholarly journals FRESH STATE PROPERTIES OF LIME MORTARS WITH FLAX OIL ADMIXTURE

2019 ◽  
Vol 22 ◽  
pp. 7-11 ◽  
Author(s):  
Pavla Bauerová ◽  
Pavel Reiterman ◽  
Milena Pavlíková ◽  
Magdalena Kracík Štorkánová ◽  
Martin Keppert
Keyword(s):  
Ftir Spectroscopy ◽  
Current Literature ◽  
Raw Materials ◽  
Water Repellency ◽  
Air Entrainment ◽  
Flax Oil ◽  
Historic Mortar ◽  
Lime Mortars ◽  
Fresh State ◽  
Ancient Times

Flax oil has been used as mortar improving, hydrophobic, admixture already in ancient times. The paper describes the identification of flax oil in mosaic mortar from ca. 1900 by help of FTIR spectroscopy. This historic mortar was reproduced by nowadays raw materials and the influence of flax oil on consistency and air entraining of fresh mortar was tested. It was found that already small amount of oil caused significant air entrainment, which, simultaneously with water repellency action, may contribute to higher durability of mortar with oil admixture. The flux oil influenced also consistency of mortar; its presence caused higher flow value of mortar. Moreover, the introduction of the paper summarizes principal knowledge about action of natural admixtures in lime mortars and plasters on basis of current literature.

scholarly journals Self-Consolidating Lightweight Concrete Incorporating Limestone Powder and Fly Ash as Supplementary Cementing Material

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3050 ◽  
Author(s):  
Khan ◽  
Usman ◽  
Rizwan ◽  
Hanif
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Normal Weight ◽  
Limestone Powder ◽  
Normal Weight Concrete ◽  
Supplementary Cementing Materials ◽  
Fresh State ◽  
Cementing Material

This paper assesses the mechanical and structural behavior of self-consolidating lightweight concrete (SCLWC) incorporating bloated shale aggregate (BSA). BSA was manufactured by expanding shale pellets of varying sizes by heating them up to a temperature of 1200 °C using natural gas as fuel in the rotary kiln. Fly ash (FA) and limestone powder (LSP) were used as supplementary cementing materials (10% replacement of cement, each for LSP and FA) for improved properties of the resulting concrete. The main parameters studied in this experimental study were compressive strength, elastic modulus, and microstructure. The fresh-state properties (Slump flow, V-funnel, J-Ring, and L-box) showed adequate rheological behavior of SCLWC in comparison with self-consolidating normal weight concrete (SCNWC). There was meager (2%–4%) compressive strength reduction of SCLWC. Lightweight aggregate tended to shift concrete behavior from ductile to brittle, causing reduced strain capacity and flexural toughness. FA and LSP addition significantly improved the strength and microstructure at all ages. The study is encouraging for the structural use of lightweight concrete, which could reduce the overall construction cost.

Influence of Cellulose Ethers on Fresh State Properties of Lime Mortars

2018 ◽  
Vol 276 ◽  
pp. 69-74 ◽  
Author(s):  
Martin Vyšvařil ◽  
Michaela Hegrová ◽  
Tomáš Žižlavský
Keyword(s):  
Water Retention ◽  
Guar Gum ◽  
Relative Yield ◽  
Point Of View ◽  
Rheological Parameters ◽  
Cellulose Ethers ◽  
Air Content ◽  
Flow Table ◽  
Lime Mortars ◽  
Fresh State

Cellulose ethers (CEs) are widely used as viscosity enhancing, water retaining additives in cement based mortars. Nevertheless, studies about the effect of cellulose ethers on the properties of aerial lime-based mortars are very lack. The use of water retaining additives in lime mortars can influence not only their fresh state properties but also the pore structure and strength of hardened mortars. In this work, four different commercial cellulose ethers were added to lime mortars in order to test their influence on properties of mortars in the fresh state. Mortar rheological parameters (relative yield stress, consistency coefficient and fluidity index) were correlated with flow table tests, relative density measurements, water retention and air content in the mortars. It was found that CEs reduce the spread of lime mortars and increase air content in the mortars. The CEs are not so effective in water retention compared with other types of water retention agents. Most dosages of CEs change the behaviour of mortars from pseudoplastic to dilatant. In contrast to the effect of CEs in cement-based materials, their viscosity enhancing behavior in lime mortars is denied, due to the presence of large amounts of calcium hydroxide. From this point of view, the CEs are not so suitable to use as viscosity enhancing admixtures in lime mortars like derivatives of chitosan or guar gum.

scholarly journals Preparation and Characterization of Ultra-Lightweight Foamed Concrete Incorporating Lightweight Aggregates

2019 ◽  
Vol 9 (7) ◽  
pp. 1447 ◽  
Author(s):  
Mohamed Abd Elrahman ◽  
Mohamed El Madawy ◽  
Sang-Yeop Chung ◽  
Pawel Sikora ◽  
Dietmar Stephan
Keyword(s):  
Thermal Conductivity ◽  
Drying Shrinkage ◽  
Lightweight Aggregate ◽  
Strength Development ◽  
Dry Density ◽  
Low Density ◽  
Wide Range ◽  
Fresh State ◽  
Foamed Concrete ◽  
Hardened State

Increasing interest is nowadays being paid to improving the thermal insulation of buildings in order to save energy and reduce ecological problems. Foamed concrete has unique characteristics and considerable potential as a promising material in construction applications. It is produced with a wide range of dry densities, between 600 and 1600 kg/m3. However, at a low density below 500 kg/m3, it tends to be unstable in its fresh state while exhibiting high drying shrinkage in its hardened state. In this study, lightweight aggregate-foamed concrete mixtures were prepared by the addition of preformed foam to a cement paste and aggregate. The focus of the research is the influence of fly ash, as well as fine lightweight aggregate addition, on the properties of foamed concrete with a density lower than 500 kg/m3. Concrete properties, including stability and consistency in the fresh state as well as thermal conductivity and mechanical properties in the hardened state, were evaluated in this study. Scanning electron microscopy (SEM) was used to study the microstructure of the foamed concrete. Several mixes with the same density were prepared and tested. The experimental results showed that under the same bulk density, incorporation of fine lightweight aggregate has a significant role on compressive strength development, depending on the characteristics of the lightweight aggregate. However, thermal conductivity is primarily related to the dry density of foamed concrete and only secondarily related to the aggregate content. In addition, the use of fine lightweight aggregate significantly reduces the drying shrinkage of foamed concrete. The results achieved in this work indicate the important role of lightweight aggregate on the stability of low-density foamed concrete, in both fresh and hardened states.

scholarly journals Acoustic insulation properties of lime mortars with natural lightweight aggregate

2019 ◽  
Vol 282 ◽  
pp. 02075
Author(s):  
Martin Vyšvařil ◽  
Libor Topolář ◽  
Richard Dvořák
Keyword(s):  
Natural Zeolite ◽  
Lightweight Aggregate ◽  
Appreciable Effect ◽  
High Ability ◽  
Frequency Range ◽  
Signal Attenuation ◽  
Acoustic Attenuation ◽  
Salt Accumulation ◽  
Acoustic Insulation ◽  
Lime Mortars

Porous pozzolan-active aggregate can be used to prepare lightweight lime mortars with high ability to salt accumulation from masonry, enhanced strengths and improved their acoustic and thermal insulation properties, or fire resistance. In this study, the effect of 3 types of natural lightweight aggregate on acoustic insulation properties of air lime mortars, NHL mortars, and cement-lime mortars has been investigated. Measurements of the signal attenuation in the frequency range of 16 Hz to 16 kHz showed the appreciable effect of binder and aggregate used in the mortars. Pumiceous aggregate caused the highest attenuation of the acoustic signal. The natural zeolite seems to be suitable aggregate to NHL and blended lime-cement plasters because it lightens the mortar and positively affects the acoustic attenuation.

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