Flow properties of finely dispersed binder

This article contains information about strengthening the under-ground parts of buildings and restoration of their bearing capacity, along with solutions of urea-formaldehyde resin and solutions based on sodium silicate (which have a number of significant drawbacks, such as short-lived strengthening, low strength of reinforced soil (0.1-0.5 MPa), brittle destruction under dynamic loads, environmental pollution), using impregnation compositions based on fine mineral binders. This compositions, with the name «Mikrodur», are obtained on the basis of air separation of Portland cement CEM I 52.5 (PC D0 M600) and fine-divided blast furnace slag. The method of preparation of suspension on the basis of finely dispersed binder is considered. The main characteristics determining the finely dispersed binder suspension, such as viscosity and stability of the injectable suspension (sedimentation), are established. It is proved that the indexes of viscosity and stability of solutions depend on the method of their preparation, water/binding ratio and chemical admixtures. A variety of finely dispersed binders grades on mineral composition allows providing ground, stone and concrete structures of underground constructions stabilization taking into account various requirements: strength enhancement and anti-filtration properties of the strengthened masses, their resistance to various aggressive influences, the possibility of hardening in conditions of negative temperature, acceleration of a strength enhancement

Flow properties of finely dispersed binder

This article contains information about strengthening the under-ground parts of buildings and restoration of their bearing capacity, along with solutions of urea-formaldehyde resin and solutions based on sodium silicate (which have a number of significant drawbacks, such as short-lived strengthening, low strength of reinforced soil (0.1-0.5 MPa), brittle destruction under dynamic loads, environmental pollution), using impregnation compositions based on fine mineral binders. This compositions, with the name «Mikrodur», are obtained on the basis of air separation of Portland cement CEM I 52.5 (PC D0 M600) and fine-divided blast furnace slag. The method of preparation of suspension on the basis of finely dispersed binder is considered. The main characteristics determining the finely dispersed binder suspension, such as viscosity and stability of the injectable suspension (sedimentation), are established. It is proved that the indexes of viscosity and stability of solutions depend on the method of their preparation, water/binding ratio and chemical admixtures. A variety of finely dispersed binders grades on mineral composition allows providing ground, stone and concrete structures of underground constructions stabilization taking into account various requirements: strength enhancement and anti-filtration properties of the strengthened masses, their resistance to various aggressive influences, the possibility of hardening in conditions of negative temperature, acceleration of a strength enhancement

Combined Effects of Bottom Ash and Expanded Polystyrene on Light-weight Concrete Properties

The benefits of using waste materials as a partial replacement for cement in high performance concrete are also discussed. This paper presents the combined effects of bottom ash TPP “Vung Ang” and expanded polystyrene aggregate on different the properties of light-weight concrete. Twenty different concrete mixtures with a water to cement ratio of 0.4 and superplasticizer to cement ratio of 0.015 were used. On the one hand, the EPS was partially replaced with (0 ÷ 40)% by volume of concrete mixture. On the other hand, the fine aggregate was replaced with (0 ÷ 30)% by mass of BA TPP “Vung Ang”. The engineering properties, including workability, density and compressive strength of light-weight concrete were investigated at different curing times. The level of decrease in the strength depends upon the replacement level of EPS and BA. Specifically, the concrete containing 40% EPS and 30% BA at 28 days of age decrease in average density and strength were 43.2% and 26.4%, respectively, in comparison with the control concrete

Effect of natural pozzolan on strength and temperature distribution of heavyweight concrete at early ages

The benefits of using mineral additive as a partial replacement for cement in heavyweight concrete are discussed. This paper presents the strength development and temperature distribution of concrete using Class F of natural pozzolan (PU) sourced from Northern part of Vietnam. Based on the results of conducted studies, strengths of the natural pozzolan concrete at different ages were generally lower than those of control concrete. The 7-day compressive strengths of concrete with 20% PU decreases mostly by 30.1% and least by 12.3% at the age of 28 days in comparison with control concrete. However, natural pozzolan increases the workability of fresh concrete up to 16.67% in comparison with control concrete. By using the computer program Midas Civil, the maximum temperatures at the center of concrete block with 100% cement and of concrete block with 80% cement + 20% PU are 65.7600C and 52.4400C, respectively, after 48 hours from the beginning of pouring. In addition, temperature difference between the central point and the environmental temperature of the control concrete are higher than heavyweight concrete using 20% PU. Meaningfully, the risk of through thermal cracking of heavyweight concrete without pozzolan are higher than heavyweight concrete PU to replace 20% of mass cement

Combined Effects of Bottom Ash and Expanded Polystyrene on Light-weight Concrete Properties

The benefits of using waste materials as a partial replacement for cement in high performance concrete are also discussed. This paper presents the combined effects of bottom ash TPP “Vung Ang” and expanded polystyrene aggregate on different the properties of light-weight concrete. Twenty different concrete mixtures with a water to cement ratio of 0.4 and superplasticizer to cement ratio of 0.015 were used. On the one hand, the EPS was partially replaced with (0 ÷ 40)% by volume of concrete mixture. On the other hand, the fine aggregate was replaced with (0 ÷ 30)% by mass of BA TPP “Vung Ang”. The engineering properties, including workability, density and compressive strength of light-weight concrete were investigated at different curing times. The level of decrease in the strength depends upon the replacement level of EPS and BA. Specifically, the concrete containing 40% EPS and 30% BA at 28 days of age decrease in average density and strength were 43.2% and 26.4%, respectively, in comparison with the control concrete

Effect of Aluminium Powder on Light-weight Aerated Concrete Properties

Light-weight aerated concrete (LAC) is produced by making LAC involves the addition of a gas-forming admixture like aluminium powder (AP) to a wet mortar mixture. In concrete during curing, AP will react with the calcium hydroxide in the mixture to form hydrogen. The amount of gas-forming is dependent on the mechanical properties requirements. The aim of the current work was to investigate the properties of aerated concrete (AC) containing 30% fly ash and various AP content, including dry density, porosity and modulus of elasticity, as well as strengths of test specimens. The results of this study showed that when AP content increased, the density of AC decreased, but its porosity increased. Whereas an increase in the amount of AP caused a decrease in both the compressive strength, tensile strength and the modulus of elasticity of ACspecimens. The investigation of newly modified AC through combination of local by-product in Vietnam would decrease the content of Portland cement was used and as well as reduce the amounts of ash and slag TPP as well as industrial waste thrown at a landfill. Therefore, assisting the thermoelectric power plants to be more environmentally friendly in the future

Combined effect of limestone fine aggregate and pozzolan on properties of high performance fine-grained concrete

This paper used the absolute volume method combined with the experiment to determine the compositions of high performance fine-grained concrete (HPFC) and presented the effect of limestone fine aggregate (LFA) and pozzolan (PU) on the HPFC properties. Test results showed that by increasing the LFA and PU, the workability of the concrete mixture decreased, the maximum slump loss after 90 minutes of mixing was 37.84%, whereas the mechanical properties of HPFC increased. The fine-grained concrete mixture containing 40% PU and LFA completely replaced material for natural sand, the compressive strength of concrete at 28-day increased about 23.87% in comparison to the control mixture. By using the standard NT Build 356, the destruction time of the four specimens tested was of 45, 63, 60 and 61 days, respectively. This result is due to the presence of PU increased the volume of the C-S-H, as well as the density of concrete structure and enhanced the strength of HPFC, thus increased destruction time of specimens used for the assessment of corrosion damage of reinforced in the concrete. The results of the current study support the use of the waste limestone from the quarries as a fine aggregate of green concrete in the future