Experimental Study on Shrinkage Strain of Cement with Different Water-Cement Ratio and Mineral Admixture

Research on shrinkage strain of Portland cement with different water-cement ratio and mineral admixture.The 25 mm×25 mm×280 mm molds are applied to produce test samples with the copper system gauge heads buried in advance,the mortar retractometer is applied to determine the inflation and shrinkage strain value of the test samples after maintained 3 d,7 d,14 d,28 d in the standard maintenance condition.Portland cement with different water-cement ratio does not appear obvious shrinkage strain in 3～7 d.The shrinkage strain value obviously increases in 7～14 d,and it is the biggest as water-cement ratio is 0.35,the smallest as water-cement ratio is 0.45.The shrinkage strain value reduce in 14～28 d.Portland cement mixed different quantity fly ash don′t appear obvious shrinkage strain as water-cement ratio is 0.4,and appear obvious shrinkage strain as water-cement ratio is 0.35 and 0.45 in 3～14 d.The shrinkage strain value of Portland cement is the smallest as the quantity of fly ash is 20%,and the biggest as the quantity of fly ash is 40%.The shrinkage strain relation of the Portland cement with different water-cement ratio and the quantity of slag is similar to the Portland cement with different water-cement ratio and the quantity of fly ash,but the value is bigger besides it is bigger than the value of Portland cement in 3～7 d.The shrinkage strain of Portland cement with different quantity of slag is obviously different with the Portland cement with different quantity of fly ash in 7～14 d.The shrinkage strain relation of the Portland cement with different water-cement ratio and the quantity of slag is similar to the Portland cement in 14～28 d,but the value is smaller in the same water-cement ratio.In the different age of Portland cement hydration reaction,the effects of water-cement ratio are different.from the engineering perspective,the shrinkage strain of Portland cement can reduce in appropriate water-cement ratio and fly ash.In the early age of hydration reaction,the shrinkage strain relation of the Portland cement with different water-cement ratio and the quantity of slag is similar to the Portland cement with different water-cement ratio and the quantity of fly ash,but in the later stage of hydration reaction,the shrinkage strain relation of the Portland cement with different water-cement ratio and the quantity of slag is similar to the Portland cement,and the value is smaller in the same water-cement ratio.