Comparison Of Compressive Strength To Alkali And Drying Shrinkage Of Different Series Of Alkali Slag Cement

Based on the related performance contrast of sodium hydroxide,sodium silicate,sodium carbonate,quick lime and sodium sulfate-quick lime four system alkali slag cement,by adding different dosage of fly ash,lime stone powder,gypsum and other admixtures(adopt mixing method),study their effects on four alkali slag cement properties,and compared with P.O 42.5 cement,and then by XRD and SEM analysis of microscopic mechanism.Main conclusions are as follows:(1)Compared the alkali ratio relative performance of four kinds of alkali slag cement.The test results show that for sodium hydroxide system,when the alkali content is 4%,the comprehensive performance is the optimal,at this point the 28 d compressive strength is 35.5MPa,28 d alkali ratio is 4.44;For sodium silicate system,when modulus is 1.5,content was 6%,the comprehensive performance is the optimal,at this point the 28 d compressive strength is 78.9 MPa,28 d alkali ratio is 6.58;For sodium carbonate-quick lime system,when sodium carbonate content is 4%,dosage of quick lime is 2%,its comprehensive performance is the optimal,at this point the 28 d compressive strength is 46.5 MPa,28 d alkali ratio is 5.81;For sodium sulfate-quick lime system,when sodium sulfate content is 4%,dosage of quick lime is 2%,its comprehensive performance is the optimal,at this point the 28 d compressive strength is 40.0 MPa,28 d alkali ratio is 5.00.(2)Study of the effects of admixture on the mechanical properties and alkali ratio of four kinds of alkali slag cement.Test results show that when sodium hydroxide system adding 30% fly ash or 30% fly ash and 5% gypsum(dihydrate gypsum and anhydrite),its strength and alkali content has a better comprehensive performance;Sodium silicate system adding 5% fly ash or 5% fly ash and 5% sulfur alumina clinker,its strength and alkali content has a better comprehensive performance;Sodium carbonate-quick lime system adding 10% limestone powder or 10% limestone powder and 5% gypsum(dihydrate gypsum and anhydrite),its strength and alkali content has a better comprehensive performance;sodium sulfate-system adding 30% fly ash or 30% fly ash and 5%gypsum(dihydrate gypsum and anhydrite),its strength and alkali content has a better comprehensive performance.(3)Study of admixture on the properties of four kinds of alkali slag cement dry shrinkage,and microscopic mechanism analysis.Test results show that:(1)the four kinds of alkali slag cement have different growth rate of dry shrinkage in a certain age,widespread early large,late small law,but except for sodium silicate system;(2)sodium sulfate system are the dry shrinkage smallest in four kinds of system when not adding admixture,while sodium silicate system is the largest;After adding 30% fly ash and 5% dihydrate gypsum,sodium sulfate system dry shrinkage rate minimum,which is also the smallest of four kinds of system,and the sodium silicate system dry shrinkage rate still the largest after adding admixture;(3)by SEM and XRD analysis can be drawn,the differences between the different series alkali slag cement dry shrinkage before and after the addition of admixture and the P.O42.5 control group are realted to their respective hydration activity and types of hydration products,crystal glue ratio.