Study on strength evolution characteristics and ratio parameter optimization of slag-phosphogypsum base wet shotcrete
In order to explore the influence of mineral admixtures on the mechanical properties of wet shotcrete,an experimental study on the mechanical properties of concrete containing mineral admixtures was carried out,and the influence rules of slag admixtures,phosphogypsum admixtures,NaOH admixtures and water reducing agent admixtures on various strength indexes of concrete were systematically analyzed.The results show that adding appropriate amount of slag and phosphogypsum can enhance various strength indexes of wet shotcrete,and phosphogypsum has the most significant improvement effect on the strength indexes,followed by slag content,and the increase of alkaline activator and water reducing agent content also has a promoting effect on the strength indexes.For each strength index,phosphogypsum content and NaOH content are the two factors that have the greatest influence,and phosphogypsum content has the greatest influence,followed by NaOH content.Phosphogypsum content and NaOH content are significant influencing factors of compressive strength at 7 days,28 days and 28 days,and phosphogypsum content is also significant influencing factor of flexural strength at 28 days.Each strength index is not only affected by a single factor,the interaction between phosphogypsum content and NaOH content can also have a significant impact on the strength index.Fuzzy comprehensive evaluation model was used to optimize the ratio parameters,and the optimal ratio scheme was obtained as follows:slag content 15％,phosphogypsum content 20％,NaOH content 2.0％and water reducing agent content 0.5％.The microstructure test shows that hydration products interweave with each other to fill the void,which gradually increases the density of the internal microstructure of the sample,and thus forms a more stable skeleton system,which provides mechanical strength for the sample.
mineral admixtureorthogonal testmechanical strengthparameter optimizationmicrostructure
万方数据
维普
