Testing of Technological Properties of Foam Concrete

2016 ◽  
Vol 865 ◽  
pp. 229-233 ◽  
Author(s):  
Karel Mikulica ◽  
Iveta Hájková

At present the demand for thermal insulation materials is bigger than ever before. Also cement foam or foamconcrete, the mixture of cement mortar and technical foam can be one of such materials. Due to its liquid consistency this material can be simply applied in fresh status on uneven board surfaces where application of common thermal insulating materials would be very complex and time consuming.This work is involved in use of fly ash in foamconcrete and polystyrene-concrete compositions; these are very lightweight concretes produced from fine-grained cement mortars by its foaming using foamable admixtures. The objective of this work is to verify whether final physical and mechanical properties are improved when fly ash is applied within the mixture, in particular, the compressive strength thermal coefficient and stability after 12 hours from mixing.

2018 ◽  
Vol 69 (8) ◽  
pp. 2040-2044
Author(s):  
Georgeta Velciu ◽  
Virgil Marinescu ◽  
Adriana Moanta ◽  
Ladislau Radermacher ◽  
Adriana Mariana Bors

The influence of fly ash adittion (90 % fraction [ 100 mm) on the cement mortar characteristics was studied. The XRD, XRF, SEM and FTIR determinations indicated that fly ash used has a hollow microstructure of microsphere and cenosphere whose total content in SiO2, Al2O3 and Fe2O3 is 88.63 % and that of CaO and MgO of 8.55 %. The mechanical, thermal and dielectric determinations made on mortar samples with content of fly ash in the 0-40 % range have highlighted fact that the mechanical strength of cement mortars is maximal at 20 %, the increase in fly ash content leads to a decrease in relative density and thermal conductivity as well as and to increased dielectric losses tgd.


Clay Minerals ◽  
2011 ◽  
Vol 46 (2) ◽  
pp. 213-223 ◽  
Author(s):  
V. Lilkov ◽  
I. Rostovsky ◽  
O. Petrov

AbstractCement mortars and concretes incorporating clinoptilolite, silica fume and fly ash were investigated for changes in their physical and mechanical properties. It was found that additions of 10% clinoptilolite and 10% Pozzolite (1:1 mixture of silica fume and fly ash) were optimal for improvement of the quality of the hardened products, giving 8% and 13% increases in flexural and compressive strength respectively. The specific pore volume of the mortars incorporating zeolite decreased between the 28th and 180th day to levels below the values for the control composition due to the fact that clinoptilolite exhibits its pozzolanic activity later in the hydration. In these later stages, pores with radii below 500 nm increased at the expense of larger pores. The change in the pore-size distribution between the first and sixth months of hydration occurs mostly in the mortars with added zeolite.


2018 ◽  
Vol 27 (3) ◽  
pp. 348-354 ◽  
Author(s):  
Jakub Jura ◽  
Małgorzata Ulewicz

The article presents the results of research aimed at using glass waste and ash from biomass. The tests were carried out for cement mortars samples with using glass cullet, ash from biomass and using both wastes in 50/50 proportions. The physical and mechanical properties of the standard mortar and modified mortars were tested. Standard mortar and cement mortar samples were made in which 10, 20 and 30% of the cement mass was used as part of the standard sand. The samples were made of CEM I 42.5R. Mortars containing fly ash addition had an increased compressive strength and a smaller drop in compressive strength after frost resistance tests than standard mortar. The use of glass cullet in the amount of up to 20% did not reveal any changes in the mechanical properties of mortars, but using them in a larger amount resulted in unfavorable results. The use of a mixture of these two waste materials did not improve the results. The research has shown the possibility of using this waste to modify cement mortars.


2021 ◽  
Vol 325 ◽  
pp. 65-70
Author(s):  
Martin Vyšvařil ◽  
Patrik Bayer ◽  
Tomáš Žižlavský

In this study, the utilization of two types of spongilites in various addition in cement mortars has been investigated with the purpose of exploring a new application of this natural pozzolans as cement mortar additives. The influence of the addition of spongilites on the physico-mechanical properties, frost-resistance, and microstructure of cement mortars as a function of time was studied. The results revealed that the rising proportion of spongilites in cement mortars causes increase in water retention of mortars, reduction of their bulk density, increase in porosity of mortars due to the growing predominance of capillary pores maintaining sufficient mortars strengths, and slightly increase in the frost-resistance of mortars. After initial tests, partial replacement of cement in fine-grained cement mortars with hitherto unexploited spongilites seems to be very promising. Based on the achieved results, a 20% cement replacement can be recommended as optimal.


2019 ◽  
Vol 891 ◽  
pp. 180-186
Author(s):  
Santi Rattanaveeranon ◽  
Sarote Dumrongsil ◽  
Knavoot Jiamwattanapong

This paper reported the effect of latex rubber (LR) and rubber powder (RP) on the bending strength of cement mortars containing fly ash silica (FAS) prepared from sugarcane bagasse. The bending strengths of the cement mortars with the addition of LR and RP were compared. The study was conducted by adding 5-10 wt% of each admixture into cement mortar specimens and left in air atmosphere for 28 days before measuring their bending strength. At 5 wt.%, both LR or RP could significantly reinforce the bending strength of the mortar. The bending strength of cement mortars decreased when the proportion of the LR and RP were higher than 5 wt%. In addition, at 10 wt%, LR provided better bending strength than that of RP, i.e. the bending strength of mortar contained LR was 550 ksc, whereas that contained RP was 85 ksc. The bending strength of mortar with LP was much higher than that of the pure cement mortar (20 wt% FAS : 80 wt% cement) which was about 62 ksc. The low bending strength of the mortar with 10 wt% RP may be due to the decrease of Si-O-Si hybrid compounds which was inhibited by the hydroxyl group during the hydrolyzation process.


2018 ◽  
Vol 276 ◽  
pp. 254-258
Author(s):  
Karel Mikulica ◽  
Dušan Dolák

In the current construction industry, great importance is given to the usage of thermally insulating building materials. One of the many such materials can be a cement foam or foam concrete, a mixture of cement mortar and technical foam. This material can be, due to its consistency right after mixing, applied to uneven horizontal surfaces where usage of conventional thermal board insulation materials would be complicated. This paper discusses the methodology of testing of the physical and mechanical properties of foaming additives such as strength, density, foaming number and half-separability of technical foams. Then this methodology was subsequently verified on the five commonly used foaming additives in the Czech Republic.


2019 ◽  
Vol 29 (5) ◽  
pp. 721-729 ◽  
Author(s):  
NR Aravind ◽  
Dhanya Sathyan ◽  
K M Mini

The major segment for energy consumption is found in industry, transport, agricultural, residential and commercial sector. The main part of the energy consumption in residential and commercial buildings is due to the use of mechanical devices to maintain a comfortable indoor environment. Thermal conductivity of building materials is one of the factors which influence the heat transfer in buildings. Thermal conductivity can be reduced by the use of materials with low density. The present paper reports the development of a sustainable thermal insulating external wall panel and its mechanical, thermal and durability properties. The wall panel was prepared using foam concrete and rice husk and replacing the cement by fly ash. Strength of panel was tested by conducting in plane bending test and compressive strength test. Thermal conductivity was tested using guarded hot plate apparatus. Durability properties were tested by conducting water absorption test, drying shrinkage and acid resistance test. The test results showed that the rice husk and fly ash content had a major influence on the thermal conductivity and durability properties of the developed wall panels.


2020 ◽  
Vol 13 (13) ◽  
pp. 24-28 ◽  
Author(s):  
Deepa Humbahadur Gurung ◽  
Vinay Kumar Jha

The world cement industry is responsible for 5-8 % of the total CO2 emission. Thus, the cement industry has a crucial role in global warming. The search for an alternative green inorganic binder with improved durability led to the discovery of alkali-activated binder termed “geopolymer”. In this study, geopolymer was synthesized from coal fly ash (CFA) with the parameters such as particle size ≤ 53 μm, NaOH concentration 8 M and the mass ratio of CFA/Na2SiO3 was 0.75. For the comparative study with fly ash based cement, the cement mortars were prepared by varying the cements and mass ratio. The highest compressive strength (14.16 MPa) of the cement mortar was however obtained with 1:3 cement sand ratio after 7 days of curing, the ratio of 1:4 was considered for comparison. The cement and geopolymer mixture mortars were also prepared with varying (cement + sand) and (CFA+ NaOH+ Na2SiO3) mass ratio. The maximum compressive strength of 3.84 MPa was obtained for 1:2 mass ratio with 7 days of curing. The maximum compressive strengths of CFA based geopolymer, CFA added cement and cement and geopolymer mixture were 17.06, 21.3 and 11.42 MPa with 90 days of curing respectively.


2011 ◽  
Vol 343-344 ◽  
pp. 316-321 ◽  
Author(s):  
Watcharapong Wongkeo ◽  
Pailyn Thongsanitgarn ◽  
Arnon Chaipanich

Cement industry is a one of the major sources of environmental pollution therefore the reduction of cement demand should be improved. Fly ash and silica fume is a by-product of industries and it should be reused to reduce the waste pollution. Thus, this study investigated the use of fly ash and silica fume as a cement replacement in binary and ternary blended cements on compressive strength and physical properties of mortar. Autoclaved curing at 130 °C and 20 psi of pressure for 9 h was used in this study. The results show that the compressive strength of binary blended cement mortar with FA tends to decrease with increased FA replacement and shows compressive strength lower than PC control. However, compressive strength of binary blended cement mortar with SF was improved and shows compressive strength higher than that of PC control. The compressive strength of ternary blended cement mortar was higher than binary blended cement at the same level replacement and it increases with increased SF replacement. Moreover, ternary blended cement mortar containing 10%SF by weight contribute in giving compressive strength higher than PC control. The incorporation of FA with SF can enhance workability of blended cement mortar containing only SF replacement.


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