| The paper uses the program of different test age, different water-binder ratio and different content of fly ash (0,20%, 40%, 60%, 80%).According to concrete elastic modulus test and ultimate tensile test, the change law of compressive elastic modulus and axial compressive strength of different water-binder ratio and different content of fly ash under 28d and 60d are analyzed.The relationship between axial tensile strength and tensile elastic modulus and the different initial condition is talked.We can get the following results:(1)The change law of compressive elastic modulus and axial compressive strength A. Both the elastic modulus and axial compressive strength would decrease with the increase of content of fly ash, so would the water-binder ratio. B. With the same content of fly ash, the elastic modulus of concrete with the water- binder ratio of 0.45 is a little bigger than that with the water- binder ratio of 0.5 under the test age of 28d or 60d. The axial compressive strength shows the same tendency. C. Under the test age of 28d, the decrease of elastic modulus of concrete with the water-binder ratio of 0.5 is quicker than that of 0.45 with the content of fly ash increasing; Under the test age of 60d, the decrease of elastic modulus of concrete with the water-binder ratio of 0.5 is slower than that of 0.45 with the content of fly ash increasing and the difference is quite small. D. With the water-binder ratio of 0.45 or 0.5, the elastic modulus of concrete under the test age of 60d is a little bigger than that of 28d, which indicates that the elastic modulus of concrete increases with the test age but the tendency is quite gentle under the premise of same content of fly ash; In the same condition, the axial compressive strength of concrete under the test age of 60d is a little bigger than that of 28d, which indicates that the axial compressive strength of concrete obviously increases with the test age but the extent is quite great under the premise of same content of fly ash.(2)The relationship between axial compressive strength and axial tensile strength of fly ash concreteA. The axial tensile strength and tensile elastic modulus of fly ash concrete become bigger with the maintenance age increasing; B. Under the test age of 28d, the axial compressive strength of fly ash concrete is almost seven times of its axial tensile strength; C. Under the test age of 60d, the axial compressive strength of fly ash concrete is almost 8- 10 times of its axial tensile strength.It indicated that the growth of axial compressive strength is bigger than of axial tensile strength; The axial compressive strength of fly ash concrete is almost 7- 10 times of its axial tensile strength.(3)The relationship between compressive elastic modulus and tensile elastic modulus of fly ash concreteUnder the test age of 28d and 60d, the variation of compressive elastic modulus and tensile elastic modulus of fly ash concrete ranges from 0.9 to 1.1, which shows little difference.The relationship between ratio of compressive strength and their elastic modulus of fly ash concrete can be expressed by cubic equation. |
