POLYESTER MORTARS WITH FINE TAILING AS FILLER

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1 POLYESTER MORTARS WITH FINE TAILING AS FILLER NakWoon Choi 1), SeongJin Yoon 2), KyoungJu Mun 2), YangSeob Soh 2) 1) Research Center of Industrial Technology, Chonbuk National University, Korea 2) Faculty of Architecture and Urban Engineering, Chonbuk National University, Korea Abstract The purpose of this study is to examine the basic properties of polyester mortars using a fine tailing () from an abandoned mine as a filler. with sizes of 1 69 μm is obtained by the centrifugal separation of tailing (TA), and tested for basic properties such as, particle shape, fineness size distribution, liquid resin absorption and heavy metal leaching. Polyester mortars with and ground calcium carbonate () are prepared with various filler-(filler+binder) ratios and replacements of with, and tested for working life, flexural and compressive strengths. As a result, has almost the same properties as in terms of particle shape, fineness size and liquid resin absorption. The working life of the polyester mortars is prolonged with increasing filler- (filler+binder) ratio and replacement of with. The flexural and compressive strengths of the polyester mortars with reach maximums at a filler-(filler+binder) ratio of 4%, but the compressive and flexural strengths of polyester mortars with decrease with increasing filler- (filler+binder) ratio. It is recommended from the viewpoint of the strength development of the polyester mortars with that the filler-(filler+binder) ratio and replacement of with should be controlled at 5% or less. 1. Introduction In South Korea, about 9 metal mines have been abandoned, and about 88 million-t metal mine wastes have been discarded in recent years. The treatment of the tailings which are the main wastes in the abandoned metal mines becomes a social problem because they cause environmental pollution such as acidic waste water generation, groundwater contamination, and dust generation. Since almost whole quantities of the tailings have disposed by landfill now, the development of effective recycling methods for the tailings are strongly requested. It is expected that the fine tailings obtained by centrifugal separation process among the tailings can be utilized as fillers for polymer mortars or concretes.

2 In this study, in order to examine the usability of a fine tailing which is obtained by a centrifugal separation process as a filler for polyester mortars, the physical and chemical characteristics of the fine tailing and the fundamental properties of the polyester mortars with the fine tailing are investigated. Especially, the practical usability of the fine tailing as a replacement material for the ground calcium carbonate currently used as a general filler for polyester mortars is evaluated. 2. Materials 2.1 Materials for binder systems Binder systems for unsaturated polyester mortars were based on a commercial unsaturated polyester resin [consisting of unsaturated polyester (UP) and styrene (ST)], together with methyl ethyl ketone peroxide as an initiator, and cobalt octoate as a promoter. The properties of the unsaturated polyester resin are listed in Table 1. Table 1: Properties of unsaturated polyester resin. Density (2, g/cm 3 ) Viscosity (2, mpa s ) Acid value Styrene content (%) Fillers and fine aggregate Commercially available ground calcium carbonate () and the fine tailing () obtained by centrifugal separation of tailings from an abandoned mine were used as fillers, and commercial silica sand was done as a fine aggregate. The water contents of the fillers and fine aggregate were controlled to be less than.1% by heat drying. The chemical compositions of the fillers are shown in Table 2. The properties of the fillers and fine aggregate are given in Table 3. Table 2: Chemical compositions of fillers. Type of Chemical compostions(%) filler SiO 2 Al 2 O 3 Fe 2 O 3 CaO MgO Na 2 O K 2 O SO 3 ig. loss Table 3: Properties of fillers and fine aggregate. Type of filler or fine aggregate Size (µm) Density (2,g/cm 3 ) Water content (%) Organic impurities < <.1 - Silica sand <.1 Nil 3. Testing procedures 3.1 Physical and chemical tests for fillers The particle shape, fineness and size distribution of fillers were tested by scanning electron microscope (SEM), Blaine air permeability apparatus and particle analyzer, respectively. The fillers for liquid resin absorption test were dried at a temperature of 15±2 C for 48h, and cooled in a desiccator. One hundred gram of the sample of each filler was weighed, mixed with

3 unsaturated polyester resin as a liquid resin to get a putty state. The mass of the filler/unsaturated polyester resin mixture was weighed, and the liquid resin absorption was calculated by the following equation. Liquid resin absorption (ml/g) = Volume of absorbed liquid resin(ml) Mass of filler (g) 3.2 Preparation of polyester mortars Binders for polyester mortars were prepared according to the formulations given in Table 4. Table 4: Binder formulations for polyester mortars. UP(%) SM(%) CoOc(phr * ) MEKPO(phr * ) Note, * phr : parts per hundred parts of resin Polyester mortars were prepared by mixing the binder with fillers and fine aggregate according to the mix proportions shown in Table 5. Table 5: Mix proportions of polyester mortars. Mix No. Filler-filler+binder ratio (%) Binder Mix proportions (%) Filler CaCO Fine aggregate Working life test for polyester mortars The working life of fresh polyester mortars was determined at 2 C according to the fingertouching method prescribed in KS F 2484 (Measuring methods for working life of polyester resin concrete). 3.4 Strength tests for polyester mortars Beam specimens mm were molded using fresh polyester mortars in accordance with KS F 2419 (Method of making polyester resin concrete specimens), and subjected to a 72h-2 C- 6%(RH)-dry cure. The specimens were tested for flexural and compressive

strengths according to KS F 2482 (Method of test for flexural strength of polyester resin concrete) and KS F 2483 (Method of test for compressive strength of polyester resin concrete using portions

The Blaine surface areas of and are 3151 and 3376cm 2 /g, respectively. Fig. 2 illustrates the particle size distribution curves for the fillers.

4 strengths according to KS F 2482 (Method of test for flexural strength of polyester resin concrete) and KS F 2483 (Method of test for compressive strength of polyester resin concrete using portions of beams broken in flexure), respectively. 4. Test results and discussion Fig. 1 represents the SEM micrographs of fillers. Both and consist of almost the same irregular-shaped particles. The Blaine surface areas of and are 3151 and 3376cm 2 /g, respectively. Fig. 2 illustrates the particle size distribution curves for the fillers. The particle size distribution of differs considerably from that of. has two peaks at particle sizes of 6.3 and 29.99µm, but has a sharp peak at about 13.75µm. The liquid resin absorptions of and are 3 and 33ml/g, respectively. A difference in the liquid resin absorption between and is hardly recognized. 2 μm 2 μm Fig. 1: SEM micrographs of fillers. Re taine d (%) Particle size( μm ) Cumulative passing(%) Re taine d (%) Particle size( μm ) Cumulative passing(%) Fig. 2: Particle size distribution curves for fillers. Table 6 gives the leaching contents of heavy metals from. The leaching contents of heavy metals excepting Pb by on the EP test method are higher than those by the KSLT test method. However, the leaching contents of heavy metals satisfy all the required limits specified in the KSLT test method and the EP test method. It is considered that their influences on the

5 environment will be slight because the heavy metals could be solidified in the polyester mortars. Table 6: Leaching contents of heavy metals from. Method of analysis Leaching content (mg/l) Cr Cu Zn Cd Pb KSLT Requirements <1.5 <3. - <.3 <3. test Results EP Requirements <5. <5. - <1. <5. test Results Fig. 3 exhibits the effect of filler-(filler+binder) ratio on the working life of polyester mortars with different fillers. The working life of the polyester mortars is lengthened with an increase in the filler-(filler+binder) ratio irrespective of the type of filler. It is found that the heat sink action of the fillers in the polymer mortars for the exotherm induced by the polymerization of the binders is increased with an increase in the filler-(filler+binder) ratio [3]. Such working life lag of the polyester mortars, caused by increasing filler-(filler+binder) ratio is remarkable in the use of rather than. Heavy metal ingredients which exist in very small quantities in may act as polymerization retardants during the hardening of the polyester mortars. Fig. 4 illustrates the effect of replacement of with on the working life of polyester mortars with different fillers at a filler-(filler+binder) ratio of 5%. By the reason described on Fig3, the working life of polyester mortars is lengthened with an increase in the replacement of with. Working life (min) Filler type Working life (min) Filler-(filler+binder) ratio=5% Filler-(binder+filler) ratio (%) Replacement of with (%) Fig. 3: Filler-(filler+binder) ratio vs. working life of polyester mortars with different fillers. Fig. 4: Replacement of with vs. working life of polyester mortars with different fillers at filler-(filler+binder) ratio of 5%. Figs. 5 and 6 show the effect of filler-(filler+binder) ratio on the flexural and compressive strengths of polyester mortars with different fillers. The flexural and compressive strengths of the polyester mortars with are decreased with increasing filler-(filler+binder) ratio. By contrast, the flexural and compressive strengths with increased with an increase in the

6 filler-(filler+binder) ratio, and reach maximums at a filler-(filler+binder) ratio of 4%. In general, the flexural and compressive strengths with tend to be lower than those with. The differences in the flexural and compressive strengths between and become larger at filler-(filler+binder) ratios of 5% or higher. This may be attributed to the action of the small quanties of heavy metals contained in. Flexural strength (MPa) Filler type Filler-(filler+binder) ratio (%) Fig. 5: Filler-(filler+binder) ratio vs. flexural strength of polyester mortars with and. Compressive strength (MPa) Filler-(filler+binder) ratio (%) Fig. 6: Filler-(filler+binder) ratio vs. compressive strength of polyester mortars with and. Figs. 8 and 9 show the effect of replacement of with on the flexural and compressive strengths of polyester mortars. The flexural and compressive strengths of the polyester mortars are increased with an increase in the replacement of with, and reach maximums at a Filler type Flexural strength (MPa) Filler-(filler+binder) ratio = 5% Replacement of with (%) Fig. 7: Replacement (%) of with vs. flexural strength of polyester mortars with different fillers at filler- (filler+binder) ratio of 5%. Compressive strength (MPa) Filler-(filler+binder) ratio = 5% Replacement of with (%) Fig. 8: Replacement (%) of with vs. compressive strength of polyester mortars with different fillers at filler- (filler+binder) ratio of 5%. replacement of 3%. From the viewpoint of the strength development, it is recommended that the replacement of with is controlled at 5% or less.

$Fig. 9 represents the SEM micrographs of fracture surfaces of polyester mortars Mix Nos. 3 and 7 with and as fillers.$ type of the filler. The particles of the fillers and fine aggregates are sufficiently covered with hardened polyester resin as a binder.

type of the filler. The particles of the fillers and fine aggregates are sufficiently covered with hardened polyester resin as a binder.

$9: SEM micrographs of fracture surfaces of polyester mortars with different fillers. 5.$ Conclusions The conclusions obtained from the test results are summarized as follows: 1) has much the same properties as in terms of particle shape, fineness size, and liquid resin

Conclusions The conclusions obtained from the test results are summarized as follows: 1) has much the same properties as in terms of particle shape, fineness size, and liquid resin

7 Fig. 9 represents the SEM micrographs of fracture surfaces of polyester mortars Mix Nos. 3 and 7 with and as fillers. From the observation of the fracture surfaces of the polyester mortars, the fracture of the polyester mortars is almost caused by the failure of the fine aggregate regardless of the type of the filler. The particles of the fillers and fine aggregates are sufficiently covered with hardened polyester resin as a binder. It is considered that the high adhesion between the fillers or fine aggregate and polyester resin is developed. 1 μm 1 μm Mix No. 3 mortar with (part 1) Mix No. 3 mortar with (part 2) 1 μm 1 μm Mix No. 7 mortar with (part 1) Mix No. 7 mortar with (part 2) Fig. 9: SEM micrographs of fracture surfaces of polyester mortars with different fillers. 5. Conclusions The conclusions obtained from the test results are summarized as follows: 1) has much the same properties as in terms of particle shape, fineness size, and liquid resin absorption. The leaching contents of heavy metals in satisfy the required levels by both KSLT and EP tests. 2) The working life of polyester mortars is prolonged with increasing filler-(filler+binder) ratio and replacement of with. 3) The flexural and compressive strengths of polyester mortars with reach macimums at a filler-(filler+binder) ratio 4%, but the compressive and flexural strengths of polyester mortars with decrease with and increase in the filler-(filler+binder) ratio.

8 4) It is recommended from the viewpoint of the strength development of polyester mortars with that the filler-(filler+binder) ratio and replacement of with should be controlled at 5% or less. References [1] M. Kuromoto, et al., Quantitative Evaluation of interfacial affinity and interaction between fillers and polymer matrix on MMA polymer mortar (In Japanese), Concrete Research and Technology, 9(2) (1998) [2] M. Kuromoto, et al., Characterization of polymer-filler interaction in MMA polymer concrete, Proceedings of the Second East Asia Symposium on Polymers in Concrete (ASPIC), College of Engineering, Nihon University, Koriyama, Japan, May 1997, [3] N.W. Choi and Y. Ohama, Influences of mix propportions on properties of polymer mortars using waste expanded polystyrene solution-based binders, Proceedings of the International Conference on Performance of Construction Materials in the New Millennium (ICPCM), Ain Shams University, Cairo, Feb. 23,

BASIC PROPERTIES OF UNDERWATER POLYMER MORTARS USING WASTE EXPANDED POLYSTYRENE-METHYL METHACRYLATE-BASED BINDERS

BASIC PROPERTIES OF UNDERWATER POLYMER MORTARS USING WASTE EXPANDED POLYSTYRENE-METHYL METHACRYLATE-BASED BINDERS Atsushi Moroka 1) and Yoshihiko Ohama 2) 1) Graduate School of Engineering, Nihon University,