Researches About Fly Ash Based Sodium Silicate Concrete

In this study, fly ash was a main research object. Sodium silicate was screened as the best adhesive by comparing the curing mechanism of different adhesives. The experiment process was designed referring to uniform design. Fly ash was a kind of solid waste which was used in many different places, to achieve the purpose of waste treat waste.The best optimal formula was selected by detecting the weight loss and compressive strength of the material. A new designed fly ash based material which conformed to the national standard was the final destination. XRD and SEM were used as two main methods in the analysis of the internal mechanism of the material.Through the study of this thesis, the conclusions as follows:(1) The best ratio of fly ash based acid resisting material is sodium silicate:Fluorine sodium silicate: fly-ash: Support material = 1:0.15-0.20:0.20:2.5(mass ratio). The compressive strength of this material is up to 16.98 Mpa, after soaking in a acid concentration of 5% simulation for 15 days, the compressive strength is 15.89 Mpa.(2) The sample’s compressive strength is lower than that of the blank sample while the acid concentration is below 15%(mass concentration); its compressive strength is higher than that of the blank sample while the acid concentration is above15%(mass concentration). While under an acid concentration of 3%, the strength loss reaches a maximum which is 6.7%.(3) Increasing of the modulus and density of sodium silicate can improve its acid resisting ability, but will shorten the coagulation time, however, it is not conducive to construction, considering all the factors above, the modulus of sodium silicate is 2.6 ~ 2.8, the density of it is advisable is 1.38 ~ 1.42 g/ml.(4) By using SEM and XRD to analysis the sample, the internal mechanism of the material was because a series of complex chemical reaction between fly ash and sodium silicate finally formed a relatively dense mesh structure. During the curing process of the sodium silicate, a large amount of silicon oxide which prove many Si-O bond was formed, as fly ash itself contains many Si-O, Al-O bonds, the combination between them improved the acid corrosion properties of the material.