Alkali activated binder, commonly known as geopolymer cement, has replaced Portland cement in the production of mortar and concrete globally over the past few years. The density, particle size distribution, and specif...Alkali activated binder, commonly known as geopolymer cement, has replaced Portland cement in the production of mortar and concrete globally over the past few years. The density, particle size distribution, and specific surface area (SSA) are important physical parameters affecting strength and durability of alkali activated binders. This study carried out tests for physical and chemical properties of the natural pozzolan and calcium hydroxide and then determines the influence of alkali solution (sodium silicate and sodium hydroxide) on strength development of natural pozzolan calcium hydroxide binders. The particle size distribution (PSD), relative densities (RD), and specific surface areas (SSA) of powder natural pozzolan and calcium hydroxide materials and for the mixture of natural pozzolan and calcium hydroxide were determined by using Blaine air permeability apparatus. The optimum proportion of 75% natural pozzolan and 25% calcium hydroxide was obtained which produces the compressive strength of 7.5 MPa at 28 days cured paste. The mixture of natural pozzolan and calcium hydroxide were further grinded at three different finenesses and the particle size gradation, specific densities, specific surface areas and mean particles sizes for the mixture were determined. The compressive strength of alkali activated binders increased with increasing curing period and fineness. The maximum compressive strength for 28 days cured specimens was 26.1 MPa which was obtained at a solution of 8 moles sodium hydroxide concentration. The test results showed that natural pozzolan materials can be used to make geopolymer binders for mortars and concretes. The geopolymer binders for mortars and concretes reduce green gas emission from cement factory but also it can be used to produce durable mortar and concrete with comparable strengths with mortars and concrete made from conventional Portland cement.展开更多
Composite briquettes containing high-phosphorus oolitic hematite and coal were produced with a twin-roller briquette machine using sodium carboxymethyl cellulose, molasses, starch, sodium silicate, and bentonite as bi...Composite briquettes containing high-phosphorus oolitic hematite and coal were produced with a twin-roller briquette machine using sodium carboxymethyl cellulose, molasses, starch, sodium silicate, and bentonite as binders. The effect of these binders on the strength of the composite briquettes, including cold strength and high-temperature strength, was investigated by drop testing and compression testing. It was found the addition of Ca（OH）2 and Na2CO3 not only improved the reduction of iron oxides and promoted dephosphorization during the reduction-separation process but also provided strength to the composite briquettes during the briquetting process; a compressive strength of 152.8 N per briquette was obtained when no binders were used. On this basis, the addition of molasses, sodium silicate, starch, and ben- tonite improved the cold strength of the composite briquettes, and a maximum compressive strength of 404.6 N per briquette was obtained by using starch. When subjected to a thermal treatment at 1200~C, all of the composite briquettes suffered from a sharp decrease in compressive strength during the initial reduction process. This decrease in strength was related to an increase in porosity of the composite briquettes. X-ray diffraction （XRD） and scanning electron microscopy （SEM） analyses showed that the decrease in strength of the composite briquettes could be caused by four factors： decomposition of bonding materials, gasification of coal, transportation of byproduct gases in the composite briquettes, and thermal stress.展开更多
Molasses was used as an alternative binder to the bentonite binder. The change in moisture absorption by pellets prepared with different iron ores and different molasses contents were investigated. Iron ore properties...Molasses was used as an alternative binder to the bentonite binder. The change in moisture absorption by pellets prepared with different iron ores and different molasses contents were investigated. Iron ore properties exerted the major effect on pellet behavior and final pellet quality. The absorbed moisture content of pellets prepared without binder, bentonite-added pellets, and molasses-added pellets were in the range of 7.72%–9.95%, 9.62%–10.84%, and 6.14%-6.69%, respectively. The wet pellet compressive strength of molasses-added pellets(43–230 N/pellet) was superior to that of bentonite-added pellets(9.47–11.92 N/pellet). The compressive strength of dried molasses-modified pellets increased to 222–394 N/pellet, which is currently the highest value achieved for dried pellets.展开更多
The effects of water/binder ratio （w/b） on the toughness behavior, compressive strength and flexural strength of engineered cementitious composites （ECC） were investigated. The w/b ratios of 0.25, 0.31, 0.33 and 0...The effects of water/binder ratio （w/b） on the toughness behavior, compressive strength and flexural strength of engineered cementitious composites （ECC） were investigated. The w/b ratios of 0.25, 0.31, 0.33 and 0.37 were selected and the specimens were tested at the ages of 7 d and 28 d. The experimental results showed that there was a corresponding increase in first cracking strength, modulus of rupture, compressive strength and flexural strength with the decrease of w/b. Within the w/b range of 0.25-0.37, higher w/b was found to have improved effects on deflection, strain hardening index and toughness index of ECC. In the permission of meeting the requirement of compressive strength grade, selecting higher w/b in mix design will help to obtain robust ECC.展开更多
The permeability,alkali silica reaction,workability and strength of GHPC(green high performance concrete) were studied in this paper.The results show that GHPC has an excellent durability and the effects of mass rat...The permeability,alkali silica reaction,workability and strength of GHPC(green high performance concrete) were studied in this paper.The results show that GHPC has an excellent durability and the effects of mass ratio of flyash to high calcium slag,water binder ratio,content of water reducer,and crushed coarse aggregate type on the workability and strength of GHPC were considerably evident.A new path for the concretes continuous development was put forward.展开更多
A method for making a automobile filter which includes impregnating a filter paper with a cross-linkable binder composition is discussed in the article. The water-based binder comprises a latex containing 80 wt% acryl...A method for making a automobile filter which includes impregnating a filter paper with a cross-linkable binder composition is discussed in the article. The water-based binder comprises a latex containing 80 wt% acrylic acid in the latex solids, and 20 wt% melthyl methacrylate, the binder also contains 5 parts of a cross-linking resin per 100 weight parts of latex solids and 5% parts of catalyst for the cross-linking resin based on the weight of the cross-linking resin. 4 wt% water-based polymer emulsion, on a solids basis, which is used to impregnate filter paper and rigidify it. Such impregnated filter paper has good dry and wet tensile strength and stiffness. The method has no impairing to the environment.展开更多
Using synthesized carboxy methyl amylopectin as organic binders for pelletizing, the dry pellet compressive strength goes up to 322.8 N per ball, dropping strength is 6.67 times per 0.5 m, and the green pellet shock t...Using synthesized carboxy methyl amylopectin as organic binders for pelletizing, the dry pellet compressive strength goes up to 322.8 N per ball, dropping strength is 6.67 times per 0.5 m, and the green pellet shock temperature reaches up to 820 ℃. The influence of the carboxy methyl amylopectin on the contact angle of iron ore surface was investigated. Compared with that having no organic binder, the surface tension increases 48 times and the capillary attraction increases 43 times. These results were obtained by using the quasi particulate model calculation. The analysis demonstrated that the behavior of polar group and organic chain structure are the reasons of improving the strength of pellet. XPS analysis indicated that polar group bonded on iron ore surface make the electron energy of 2p orbit of Fe decreases from 711 eV to 710.2 eV. The results showed that the special spatial reticular structure of organic chain can improve pellet strength and green ball shock temperature.[展开更多
The ceramic setting binders obtained by means of the raw mix mechano-chemical processing(mechanical dispersion and chemical interaction processes combination), used for bonding refractory concretes, become more availa...The ceramic setting binders obtained by means of the raw mix mechano-chemical processing(mechanical dispersion and chemical interaction processes combination), used for bonding refractory concretes, become more available with a subsequent increased interest in their properties because they develop initial strength during a heat up of the units within 8-10 h, in contrast to 24 h after placement for high Al_2O_3 cements(HAC). This strength development enables high temperature processing units to be relined with minimum turnaround time, thus providing a favored cost/performance ratio. The present paper identifies the predominant phosphate phases responsible for developing good mechanical-strength properties of zirconia and alumina concretes bonded with mechano-chemical binders. It sets out the colloid and crystalline phases resulted from interphase interaction that provide the basis for high concentrated bonding suspensions(HCBS) technology useful to the refractory industry.展开更多
文摘Alkali activated binder, commonly known as geopolymer cement, has replaced Portland cement in the production of mortar and concrete globally over the past few years. The density, particle size distribution, and specific surface area (SSA) are important physical parameters affecting strength and durability of alkali activated binders. This study carried out tests for physical and chemical properties of the natural pozzolan and calcium hydroxide and then determines the influence of alkali solution (sodium silicate and sodium hydroxide) on strength development of natural pozzolan calcium hydroxide binders. The particle size distribution (PSD), relative densities (RD), and specific surface areas (SSA) of powder natural pozzolan and calcium hydroxide materials and for the mixture of natural pozzolan and calcium hydroxide were determined by using Blaine air permeability apparatus. The optimum proportion of 75% natural pozzolan and 25% calcium hydroxide was obtained which produces the compressive strength of 7.5 MPa at 28 days cured paste. The mixture of natural pozzolan and calcium hydroxide were further grinded at three different finenesses and the particle size gradation, specific densities, specific surface areas and mean particles sizes for the mixture were determined. The compressive strength of alkali activated binders increased with increasing curing period and fineness. The maximum compressive strength for 28 days cured specimens was 26.1 MPa which was obtained at a solution of 8 moles sodium hydroxide concentration. The test results showed that natural pozzolan materials can be used to make geopolymer binders for mortars and concretes. The geopolymer binders for mortars and concretes reduce green gas emission from cement factory but also it can be used to produce durable mortar and concrete with comparable strengths with mortars and concrete made from conventional Portland cement.
基金financially supported by the National Natural Science Foundation of China(No.51134002)
文摘Composite briquettes containing high-phosphorus oolitic hematite and coal were produced with a twin-roller briquette machine using sodium carboxymethyl cellulose, molasses, starch, sodium silicate, and bentonite as binders. The effect of these binders on the strength of the composite briquettes, including cold strength and high-temperature strength, was investigated by drop testing and compression testing. It was found the addition of Ca（OH）2 and Na2CO3 not only improved the reduction of iron oxides and promoted dephosphorization during the reduction-separation process but also provided strength to the composite briquettes during the briquetting process; a compressive strength of 152.8 N per briquette was obtained when no binders were used. On this basis, the addition of molasses, sodium silicate, starch, and ben- tonite improved the cold strength of the composite briquettes, and a maximum compressive strength of 404.6 N per briquette was obtained by using starch. When subjected to a thermal treatment at 1200~C, all of the composite briquettes suffered from a sharp decrease in compressive strength during the initial reduction process. This decrease in strength was related to an increase in porosity of the composite briquettes. X-ray diffraction （XRD） and scanning electron microscopy （SEM） analyses showed that the decrease in strength of the composite briquettes could be caused by four factors： decomposition of bonding materials, gasification of coal, transportation of byproduct gases in the composite briquettes, and thermal stress.
文摘Molasses was used as an alternative binder to the bentonite binder. The change in moisture absorption by pellets prepared with different iron ores and different molasses contents were investigated. Iron ore properties exerted the major effect on pellet behavior and final pellet quality. The absorbed moisture content of pellets prepared without binder, bentonite-added pellets, and molasses-added pellets were in the range of 7.72%–9.95%, 9.62%–10.84%, and 6.14%-6.69%, respectively. The wet pellet compressive strength of molasses-added pellets(43–230 N/pellet) was superior to that of bentonite-added pellets(9.47–11.92 N/pellet). The compressive strength of dried molasses-modified pellets increased to 222–394 N/pellet, which is currently the highest value achieved for dried pellets.
基金Funded by the National Natural Science Foundation of China (No.50872127)the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry
文摘The effects of water/binder ratio （w/b） on the toughness behavior, compressive strength and flexural strength of engineered cementitious composites （ECC） were investigated. The w/b ratios of 0.25, 0.31, 0.33 and 0.37 were selected and the specimens were tested at the ages of 7 d and 28 d. The experimental results showed that there was a corresponding increase in first cracking strength, modulus of rupture, compressive strength and flexural strength with the decrease of w/b. Within the w/b range of 0.25-0.37, higher w/b was found to have improved effects on deflection, strain hardening index and toughness index of ECC. In the permission of meeting the requirement of compressive strength grade, selecting higher w/b in mix design will help to obtain robust ECC.
文摘The permeability,alkali silica reaction,workability and strength of GHPC(green high performance concrete) were studied in this paper.The results show that GHPC has an excellent durability and the effects of mass ratio of flyash to high calcium slag,water binder ratio,content of water reducer,and crushed coarse aggregate type on the workability and strength of GHPC were considerably evident.A new path for the concretes continuous development was put forward.
文摘A method for making a automobile filter which includes impregnating a filter paper with a cross-linkable binder composition is discussed in the article. The water-based binder comprises a latex containing 80 wt% acrylic acid in the latex solids, and 20 wt% melthyl methacrylate, the binder also contains 5 parts of a cross-linking resin per 100 weight parts of latex solids and 5% parts of catalyst for the cross-linking resin based on the weight of the cross-linking resin. 4 wt% water-based polymer emulsion, on a solids basis, which is used to impregnate filter paper and rigidify it. Such impregnated filter paper has good dry and wet tensile strength and stiffness. The method has no impairing to the environment.
文摘Using synthesized carboxy methyl amylopectin as organic binders for pelletizing, the dry pellet compressive strength goes up to 322.8 N per ball, dropping strength is 6.67 times per 0.5 m, and the green pellet shock temperature reaches up to 820 ℃. The influence of the carboxy methyl amylopectin on the contact angle of iron ore surface was investigated. Compared with that having no organic binder, the surface tension increases 48 times and the capillary attraction increases 43 times. These results were obtained by using the quasi particulate model calculation. The analysis demonstrated that the behavior of polar group and organic chain structure are the reasons of improving the strength of pellet. XPS analysis indicated that polar group bonded on iron ore surface make the electron energy of 2p orbit of Fe decreases from 711 eV to 710.2 eV. The results showed that the special spatial reticular structure of organic chain can improve pellet strength and green ball shock temperature.[
文摘The ceramic setting binders obtained by means of the raw mix mechano-chemical processing(mechanical dispersion and chemical interaction processes combination), used for bonding refractory concretes, become more available with a subsequent increased interest in their properties because they develop initial strength during a heat up of the units within 8-10 h, in contrast to 24 h after placement for high Al_2O_3 cements(HAC). This strength development enables high temperature processing units to be relined with minimum turnaround time, thus providing a favored cost/performance ratio. The present paper identifies the predominant phosphate phases responsible for developing good mechanical-strength properties of zirconia and alumina concretes bonded with mechano-chemical binders. It sets out the colloid and crystalline phases resulted from interphase interaction that provide the basis for high concentrated bonding suspensions(HCBS) technology useful to the refractory industry.
