• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.74-81
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• 1993

This experiment was carried out to investigate the reaction of hydration of paper sludge during the setting of portland cement in a paper sludge, wood-cement-water mixturte. The percentage of paper sludge per cement is 7.5%, 15%, 30% respectively. The result indicated that the sludge of 7.5% had the most effect on reaction of hydration, and the sludge of 15% had moderately inhibitory effect but there is still possibility to make sludge-cement board. Paper sludge of 30%, Pinus koraiensis Sieb. et Zucc and Populus euramericana Guinier were proved to have the worst inhibitory effect on cement hydration, so pretreatment will be needed before making board with paper sludge-cement mixture.

• Journal of the Korean Wood Science and Technology
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• v.22 no.2
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• pp.37-45
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• 1994

The possibility of reusing the paper sludge as a raw material of composition board mixed with cement was investigated. For the measurement of physical and mechanical properties, wood coment board and sludge combinend cement boards were fabricated with the three weigh ratios of paper sludge 10 % (SI), 20 % (S II) and 30 % (S III) to cement weight. For adding the cement hardning, $CaCl_2$ was also added to each mixed paste with the ratio of 1 %, 3 % and 5 % to cement weight, respectively. Crystal formation in paper sludge-, wood-cement composites was observed by scanning electron microscope. The results were summarized as follows. 1. Density and partial compressive strength of each specimens were relatively high in the order of sludge I, sludge II, Korean pine, Italian poplar and sludge III, sludge I, Korean pine, sludge II, Italian poplar and sludge III. 2. The mechanical properties of sludge-cement boards (S I and II) were higher than that of wood-cement boards prepared with Korean pine and Italian poplar. But the mechanical properties of wood-cement boards were improved by the adding of $CaCl_2$. 3. Water absorption and thickness swelling were increased with increase of sludge content to cement weight. 4. In SEM observation, sludge-cement composites showed sufficiently formed crystals but wood-cement composites showed poorly formed crystals.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.555-559
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• 2001

A by-product, waste sludge water produced from ready mixed concrete(remicon) factories may affect our environmental contamination if it is discharged without proper waste disposal. In Korea, all waste sludge water has been recycled in the way of mixing water of remicon, but the quality of the concrete then produced can be deteriorated, so it might cause slump loss or irregular compressive strength. In this study, waste sludge water is divided into two parts, remicon sludge and residual water in order to make it's property more stable. Then, the remicon sludge and high-alkaline residual water were used as admixture and alkali activator respectively. In this paper we research about quality of with remicon sludge and residual water and performed the fundamental properties of cement matrix mixed with remicon sludge and residual water.

• Resources Recycling
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• v.25 no.6
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• pp.58-64
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• 2016

Paper industry discharges many by-products and quantity of PSA (Paper sludge ash) has been increased. In this study, hydration water was added to PSA for use as cement admixture. PSA with added water was mixed with anhydrite and this mixture was used as cement substitute. Physical properties of PSA cement were changed by contents of PSA, but PSA cement containing PSA less than 10% had similar properties to those of OPC. Compressive strength of PSA cement mortar had a certain relationship with $Ca(OH)_2$ content. Compressive strength at 3 days increased, as $Ca(OH)_2$ content increased. However, the strength at 28 days increased, as $Ca(OH)_2$ content decreased.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.253-262
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• 2019

This paper described the evaluation results on unconfined compressive strength characteristics of CLSM with paper sludge ash, in order to develop a CLSM that can prevent sewer pipe damage. The flowability test and the unconfined compressive strength test were performed according to mix design condition of CLSM. The flowability test result showed that the water content, which can satisfy the flowability criteria, was 24% to 32% according to the mix design condition. The results of unconfined compressive strength test showed that the strength incremental ratio was high between 1 and 7 days of curing time, and the strength at this time was more than about 50% of the strength at 28 days of curing time. The strength of CLSM was greatly influenced by fly ash. However, it was analyzed that the mixture of paper sludge ash is required when the reference strength of CLSM is considered. Although the strength of the high cement ratio was higher than that of the low cement, a cement ratio of 5% would be a reasonable mix design condition of CLSM.

• Journal of the Korean GEO-environmental Society
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• v.13 no.8
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• pp.75-84
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• 2012

In this paper, strength and leaching characteristics of water sludge-added lightweight soils(WALS) considering reinforcing materials(waste fishing net, glue treated waste fishing net and geogrid) and layer(1 or 2 layer) were investigated using unconfined compression test and leaching test. Several specimens of water sludge-added lightweight soil consisted of water sludge, cement, and bottom ash were prepared according to flowability. Reinforcing material added into these specimens were waste fishing net and geogrid. A glue treated waste fishing net was also added in order to increase interlocking between soil mixture and waste fishing net. Strength increased in the order of WALS reinforced by waste fishing net, glue treated waste fishing net, and geogrid. Strength of specimen with double layer-reinforcing material was greater than that of specimen with single layer reinforcing material. Leaching result of WALS was also satisfied with standard of ministry of environment.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.146-152
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• 2018

In the construction sector, new demands for aesthetics are increasing due to structural stability and improvement of living standard and consciousness level. On the other hand, Red Mud sludge is generated from aluminum hydroxide extraction process from Bauxite. Red mud sludge contains about 20% of $Fe_2O_3$ and represents a natural reddish brown. It is highly applicable to the construction industry. In this paper, red mud sludge with a water content of 50%, which is a by - product of the industry, was prepared as a liquid phase. The liquefied red mud was added to cement mortar and the strength and color difference of cement mortar were investigated according to the addition amount of liquefied red mud. As a result, the compressive strength decreased with increasing amount of liquefied red mud. The color of cement mortar containing liquefied red mud was found to be distributed in the range of YR series in all samples. As the amount of liquefied red mud increased, the color became darker.

• Journal of Power System Engineering
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• v.20 no.5
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• pp.86-91
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• 2016

This paper is concerned chiefly with the method of porous foam manufacture using basalt stone powder sludge. The hydrogen peroxide($H_2O_2$) of bloating agent has lots of problems to manufacture porous lightweight aggregate due to fast reaction rate with cement or calcium hydroxide($Ca(OH)_2$). The $H_2O_2$ injecting method using nozzle for manufacturing porous lightweight aggregate is proposed, in this study. This method is to inject $H_2O_2$ at the pressure of 10 MPa on upper side of slurry mixing materials such as stone powder sludge and quick-lime(CaO) by injector. The specimen was dried in furnace at $100^{\circ}C$ for 1 hour and cured at ambient temperature for 30 days. We analyzed the characteristics including specific gravity and water absorption. The experiments were found that the porous foam has low specific gravity, high water absorption and uniform distribution of porous more than manufactured foam by general bloating methods.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.388-395
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• 2016

This paper explores the photocatalytic sensitivity of cement mortar incorporated with recycled $TiO_2$ from waste water sludge. Basically, $TiO_2$ cluster sank down slowly to the bottom of cement mortar specimen before setting and hardening process. This leads the mismatch of $TiO_2$ concentration on the top and the bottom faces of a specimen. This poorly dispersed $TiO_2$-cement mortar naturally exhibits poor NOx removal efficiency especially on the top of cementitious structure. In architectural engineering application such as building or housing structures, one can simply filp over from the bottom so that more $TiO_2$ concentrated surface can be placed outward into the air. However, in highway pavement case, this could not be applicable due to in-situ installation of concrete pavement. Hence, the dispersion of $TiO_2$ cluster inside the cementitous material is getting important issue onto road construction application. To elaborate this issue, according to our results, silica fume, high-ranged water reducer, viscosity agent, blast furnace slag were not enhanced much of dispersion characteristics of $TiO_2$ cluster. The combination of foaming agent and accelerator of hardening with viscosity agent and small grain size of fine aggregate may help the dispersion of $TiO_2$ inside cementitious materials. Even though the enhanced dispersion were applied to the specimen, NOx removal efficiency doest not change much for the top surface of the specimen. This concurrently affected by the presence of tiny air voids and the dispersion of $TiO_2$ in that these voids could easily adsorbed NOx gas with the aid of large surface area.