Use fly ash for the production of lightweight building materials

Fly ash is a waste byproduct of thermal power plants or steel plants with a low density. Study on using fly ash to produce lightweight construction materials will is a new application of this material resource. Pha Lai fly ash is a byproduct from Pha Lai Thermal Power Joint Stock Company, in which the main mineral component was mullite (15-20%), quartz (14-16%), carbon (5-7%). The content of the amorphous component was about 67-73%. The chemical composition of Pha Lai mainly was SiO2 (51.73%), Al2O3 (23.22%), Fe2O3 (4.23%). To fabricate the lightweight material from Pha Lai fly ash, the fly ash was mixed with additive materials to create binders following two ways: (1) lime + fly ash and (2) geopolymer technology. For the way of lime + fly ash, with the optimal mixture ratio was fly ash:lime: water = 10:2:1, the lightweight material samples had the bulk density of 1.32g/cm3, the compressive strength of 3.91 MPa, satisfied the Vietnamese standard TCVN 6477-2011 for concrete bricks. Applying the geopolymer technology, with the optimal mixture ratio was fly ash: NaOH/Na2SiO3: Al powder = 100:45:0.15, NaOH/Na2SiO3 ratio = 1:2, the lightweight materials obtained the bulk density of 0,62g/cm3, the compressive strength of 1,54 MPa, satisfied the Vietnamese standard TCVN:9029-2017 for Lightweight concrete - Foam concrete and non-autoclaved concrete products-specification.

Review of Basalt Fiber-Reinforced Concrete in China: Alkali Resistance of Fibers and Static Mechanical Properties of Composites

Research on three-dimensional, randomly distributed BFRC in China is analyzed and summarized in relative depth in this study. The results indicate that the effect of the fiber component and alkali corrosion temperature on the alkali resistance of BF is significant; the BF has little effect on the compressive strength of the concrete; the tensile and flexural strengths of the composites significantly increase compared with plain concrete, and the fiber content has a significant effect on the strength. In light of some problems in the current research, six possible research topics are suggested: (1) investigating the alkali resistance of the BF under dynamic temperatures, lower alkali concentrations, and longer alkali corrosion times; (2) improving the alkali resistance of the BF by increasing its hydrophobicity; (3) determining the optimal fiber distribution orientation of the BF with various characteristic parameters; (4) establishing the calculation formulas for the critical content and critical aspect ratio of various types of BF; (5) determining the optimal mixture ratio of two or more fibers in the FRC while studying the complementary mechanisms between each other; and (6) improving the dispersion of the BF and the BF/matrix interfacial properties.

Preparation Thermal Insulation Masonry Mortar Using Regeneration Light Sand

In this paper, ecotype cementing materials (with steel slag, mineral slag etc. as the main raw materials), waste aerated concrete, regeneration light sand and etc. were used as the main materials to prepare thermal insulation masonry mortar. Then the impacts of materials on the mortar’s performances such as strength, density and thermal conductivity were analyzed. At last, it obtained the optimal mixture ratio to prepare thermal insulation masonry mortar with a strength degree of M5. This kind of mortar used a lot of solid wastes as raw materials but with many advantages such as light weight, low thermal conductivity and low cost, all of this made it became a new environmental friendly thermal insulation masonry mortar.

Study on Preparation and the Setting Time of Magnesium Phosphate Cement

This paper mainly researched on preparation and the setting time of Magnesium Phosphate Cement (MPC). The method of orthogonal experiment was adapted to determine the best ratio of MPC, and change the content and types of the material according to the influence of various factors, so as to get the longer setting time of MPC. The results showed that, when the water cement ratio is 0.12, the factors significantly influencing the setting time is magnesium phosphorus ratio (M/P), fly ash and borax. The optimal mixture ratio was obtained through the orthogonal analysis, namely M/P is 3/1, borax content is 16%, and the amount of fly ash is 40%. When M/P is 1/1 and 2/2, borax content is not more than 22%, and the amount of fly ash was less than 60%, the longer setting time of MPC can be produced.

Based on the Orthogonal Design to Study the Design and Optimization of Material Composition for Curing Compound

Wax emulsion was modified by adding high polymer latex,in order to improve the film-forming ability and sealing ability of wax emulsion,and improve the brittleness of parafilm to prevent it from cracking. By orthogonal design experiment to analysis the dosage of various materials for curing compound,and based on effective water retention and concrete compressive strength ratio the two indicators to determine the optimal mixture ratio of curing compound.

Study on Test and Practical Application of Solidification Treatment of Wasted Mud

In the process of drilling and cast-in place pile, which usually produces a large amount of wasted mud. If the wasted mud had been mishandled, which may result in serious environmental problems. Combined with engineered examples, this paper mainly elaborates some common techniques related to the solidification treatment of wasted mud, the laboratory solidified test were done on the basis of the existed technical methods. The effect and cost of solidification treatment using different solidification agents were comparatively analyzed according to the result of test. Finally, in order to purpose of the optimal environmental and economic benefits, the suitable solidification treatment method and optimal mixture ratio are put forward to deal with the engineered problems.

Experimental Investigation of Three-Phase Foam Sealing Material for Fractured Borehole

To develop a kind of ideal sealing material, uniform experiments were conducted in a simulation test device after the determination of material composition and approximate ratio range. The experimental data was fitted by stepwise regression analysis and optimal mixture ratio was obtained. The reliability is perfect when the ratio of foaming agent FP, foam stabilizer WP, solid filler RX and solid filler GX is 1.5:2:3:3. Field application tests show that sealing material in the above ratio has advantages of less time waste, higher reliability and better adaptability. It has a wide application prospect for fractured borehole sealing.