USE MAGNESIA CEMENTS FOR RECEPTION HEAT INSULATING MATERIALS

Transcription

1 USE MAGNESIA CEMENTS FOR RECEPTION HEAT INSULATING MATERIALS Sergii G. Guzii 1, Boris Ya. Konstantinovskii 2 The Kyiv National University of Civil Engineering and Architecture, Kyiv, Ukraine Abstract. Composition heat insulating materials on a magnesia-based cement with the combined type filler, submitted by a mix sintered perlite sand and vermiculite in the ratio 50:50, intended for manufacture slabby heat insulating materials of the European sizes are optimized. It is marked, that in a range of change of varied factors on Х 1 - from 0,8:1 up to 1.2:1, and on Х 2 - from 2,5 up to 7,5 %, concerning to top left quadrant the full factorial field, the received artificial material is characterized by values of average density in limits from 600 up to 750 kg/m 3, values of factor of heat conductivity from 0,2 up to 0,279 Watt/m К, strength parameters as at compression (2,8-5,6 МРа), and at a flexure (2,1-3,2 МРа). On the last publications [1-7] it is visible, that magnesia cement is claimed not only in Ukraine, but also in Russia; it is perspective binders substance for reception of wide scale nonflammable heat insulating building materials as plates of various thickness from 10 up to 100 mm in the sizes 1,2х2 m. In the first publication [8] devoted perlite-magnesite as new heat insulating a material, it is marked, that application magnesia cement for manufacture heat insulating products on a basis sintered perlite sand (silicate-perlite, glass-perlite, gypsum-perlite, concrete-perlite) received by a method of moist pressing, is preferable in comparison with other binders substances, namely: at identical values of compression strength - from 1,5 up to 4 МПа, average density - from 400 up to 800 kg/m 3 and factor of heat conductivity - from 0,08 up to 0,26 W/m К, the charge magnesia cement makes size about kg on 1 m 3, that in 1,1-2,8 times it is less in comparison with application of other kinds of binders substances. Also in the given work it is marked, that perlitemagnesite products essentially differ from above resulted and fibrolite that are not inclined to swelling at surplus of a moisture and not exposed warping. Unique lack, in our opinion, is difficulty on the given kind filler, manufacturing slabby heat insulating materials of the European sizes 1,2х2 m, thickness from 10 up to 50 mm. Therefore the purpose of the given work is research of an opportunity of reception on a basis magnesia cement heat insulating materials of the above-stated sizes on vibrating technology. For carrying out of researches, in quality: binders, used a powder caustic magnesite; solitude - a solution of chloride magnesium in density of 1240 kg/m 3, the accelerator hardening a solution of chloride sodium in density of 1240 kg/m 3 ; reinforce additives - basalt scales; filler sintered perlite and vermiculite size 0,163-0,63 mm and 1-2 mm accordingly in the ratio 50:50; 1 2 Sergii G. Guzii, senior lecturers, PhD(Eng)., The Kyiv National University of Civil Engineering and Architecture, Kyiv, Ukraine Boris Ya. Konstantinovskii, senior lecturers, PhD(Eng)., The Kyiv National University of Civil Engineering and Architecture, Kyiv, Ukraine V - 95

2 volumetric hydrophobisation additives - sodium polyethyl- and sodium ethyl-hydrosiliconate. From researched structures heat insulating the mixes described by rigidity 3-4 сек, a method of formation made samples - test beam in the sizes 4х4х16 cm which after day hardening subjected to drying at temperature 105±5 о С within 24 hour. Physic mechanical properties of a material determined according to the working specifications and technical documentation, values of factor of heat conductivity estimated under Nekrasov's formula [9]. Optimization of structure heat insulating a material carried out with the help of a twofactorial three-level method of planning of experiment [10]. As varied factors are chosen: a ratio between magnesia cement and filler Х 1 and % the contents reinforce additives Х 2 which changes are resulted in tab. 1. It is necessary to note, that changes of varied factors were considered in a range: on Х 1 - from 0,4:1 up to 1,2:1, and on Х 2 - from 2,5 up to 12,5 % [11]. In clause researches of influence of varied factors on target parameters which are in left top quadrant a factorial field are resulted. As functions of the response changes of values of average density, factor of heat conductivity, strength are accepted at compression and a flexure (by tab. 2 and fig. 1). Natural Factors, kind Coded Table 1 - the Initial data Bottom -1 Levels of a variation Average 0 Top +1 Interval of a variation MC:F*, в.ч. Х 1 0,8:1 1:1 1,2:1 0,2:1 RD, % Х 2 2,5 5,0 7,5 2,5 The note: МC:F* - a ratio between magnesia cement (МC) and filler (F) in weight parts; the RD - reinforce the additive, % from weight МC. As a result of mathematical processing experimental data the adequate equations of regress are received and diagrams of change of target parameters in dependence of ratio of varied factors are constructed. The equations of regress (heat insulating a material after drying at temperature 105±5 о С within 24 hour): - Average density ρ, kg/m 3 (by Fisher's criterion F calculation =13,22<F tabular =19,3): у=655,996+25,683х 1-42,633Х 2 +12,872Х ,792Х ,875Х 1 Х 2 ; - Factor of heat conductivity λ, W/m К (by Fisher's criterion F calculation =4,79<F tabular = 19,3): У=0,232+0,013Х 1-0,021Х 2 +0,006Х 11 +0,015Х 22 +0,013Х 1 Х 2 ; - Compression strength R compressive, МPа (by Fisher's criterion F calculation =8,35<F tabular = 19,3): у=3,694+0,647х 1 +0,453Х 2-0,004Х 11 +0,366Х 22 +0,07Х 1 Х 2 ; - Flexural strength R flexure, МPа (by Fisher's criterion F calculation = 5,87<F tabular = 19,3): V - 96

3 у=2,064+0,27х 1 +0,087Х 2 +0,383Х 11 +0,373Х 22-0,002Х 1 Х 2. Table 2 - the Plan of experiment and results of its realization Points of the plan Matrix of the plan in sizes: Coded Natural Х 1 Х 2 MC:F RD, % Target parameters (the ambassador hardening samples in conditions of drying at temperature 105±5 о С during 24 hour) ρ, kg/m 3 λ, W/m К R compressive, МPа R flexure, МPа ,2:1 7,5 748,3 0,2783 5,36 3, ,2:1 2,5 749,5 0,2789 4,12 3, ,8:1 7,5 591,6 0,2001 3,96 2, ,8:1 2,5 696,3 0,2522 3,0 2, ,2:1 5,0 645,3 0,2268 4,20 2, ,8:1 5,0 701,1 0,2546 2,84 2, :1 7,5 615,1 0,2120 4,12 2, :1 2,5 765,0 0,2868 3,60 2, :1 5,0 662,0 0,2351 4,0 2, :1 5,0 650,0 0,2292 4,2 2, :1 5,0 630,0 0,2193 3,9 1,95 The analysis of the equations of regress has shown, that change of average density and factor of heat conductivity most essentially is influenced with the contents of quantity magnesia cement in composite - factor Х 1 ; on compression parameters - joint action of factors Х 1 and Х 2. а) b) V - 97

4 c) d) Fig. 1. Influence of varied factors on change of properties heat insulating a material after heat treatment at temperature 105 о С: a - average density ρ, kg/m 3 ; b - factor of heat conductivity λ, W/m К; c - Compression strength R compressive, МPа; d - Flexural strength R flexure, МPа The analysis of experimental data (fig. 1) shows tab. 1, that changing quantity magnesia cement in relation to filler, it is possible to receive heat insulating a material in a wide range of average density - from 600 up to 750 kg/m 3 at enough high parameters of durability as at compression (2,8-5,6 МPа), and at a flexure (3,1-3,2 МPа). According to work [2] in products hardening magnesia cement after day hardening, and also after drying, are fixed new formation the following structure: 5MgO MgCl 2 13H 2 O and Mg(OH) 2. Structure of an artificial stone dense (fig. 2, а) and products of hydration densely enough envelop filler and reinforce the additive (fig. 2, b). a) b) Fig. 2. Structures heat insulating material after drying at temperature 105 о С: a - the ground and scanned surface heat insulating material; b - it is finished shooting with the help of a digital microscope at increase х 500 V - 98

5 Generalizing the received data, the following is possible to tell: - The basic opportunity of reception heat insulating materials on a basis magnesia cement with the combined type filler, submitted by a mix sintered perlite sand and vermiculite in the ratio 50:50, intended for manufacture slabby heat insulating materials of the European sizes is established; - As a result of the lead optimization of structure heat insulating a material received on a basis magnesia of cement, in a range of change of varied factors on Х 1 - from 0,8:1 up to 1,2:1, and on Х 2 - from 2,5 up to 7,5 %, concerning to top left quadrant a full factorial field, it is established, that the received artificial material is characterized by values of average density in limits from 600 up to 750 kg/m 3, values of factor of heat conductivity from 0,2 up to 0,279 W/m К, strength parameters as at compression (2,8-5,6 МРа), and at a flexure (2,1-3,2 МРа); - It is shown, that change of parameters of average density and factor of heat conductivity most essentially is influenced with the contents of quantity magnesia cement in structure of a composite - factor Х 1 ; on compression parameters - joint action of factors Х 1 and Х 2; - It is recommended to application in quality constructional and heat insulating a material. The literature [1] Derevyanko V.N., Poltavcev А.P., Макsimenko А.А, Коndrateva N.V. Problems of development and manufacturing of products on a basis magnesia binders // Bulletin ОGASA. - Number 35 - Odessa: City of masters, P [2] Zimich V.V., Кramar L.Ya. Formation of structure and properties magnesia stone modified by connections of two and trivalent metals [the Electronic resource] - The Collection of reports of 3-rd (XI) International meeting in chemistry and technologies of cement, on October, 27-29, 2009, Moscow, Expocentre. - P [3] Zyrjanova V.N., Berdov G.I. Waterproof composite magnesia binders with use natural and anthropogenic raw material [the Electronic resource] - The Collection of reports of 3-rd (XI) International meeting in chemistry and technologies of cement, on October, 27-29, 2009, Moscow, Expocentre - P [4] Kramar L.Ya. Magnesia binders for construction - prospects and use. - [the Electronic resource] - The Collection of reports of 3-rd (XI) International meeting in chemistry and technologies of cement, on October, 27-29, 2009, Moscow, Expocentre. - P [5] Lotov V.A., Мitina N.A. Hydraulic binders on a basis magnesia cement. - [the Electronic resource] - The Collection of reports of 3-rd (XI) International meeting in chemistry and technologies of cement, on October, 27-29, 2009, Moscow, Expocentre. - P [6] Кozlova V.К., Sutula I.G., Manoha A.M., Guschin Е.Н Ways of elimination crack formation magnesia a stone on the basis of highly active magnesia binder hardening. - [the Electronic resource] - The Collection of reports of 3-rd (XI) International meeting in chemistry and technologies of cement, on October, 27-29, 2009, Moscow, Expocentre. - With [7] Mirjuk O.A. Magnesia composition oxychloride hardening. - [the Electronic resource] - The Collection of reports of 3-rd (XI) International meeting in chemistry and technologies of cement, on October, 27-29, 2009, Moscow, Expocentre. - P [8] Petuhova G.N. Perlitomagnezit - new heat insulating a material // Magazine Building materials and products P [9] Komohov P.G., Gryzlov V.S. Structural mechanics and thermophysics of easy concrete. - Volgograd: Publishing house of the Volgograd centre of science, p. [10] Ahnazarova S.L., Кafarov V.V. Method of optimization of experiment in chemical technology. - M.: the Higher school, p. [11] Guzii S.G., Konstantinovskii B.Ya. Heat insulating products on a basis magnesia cement // Magazine Building tender P V - 99