With the same amount of cementitious material, compressive strength of AAS concrete is 2～4 times and the permeability is 1/3～1/5 times comparison with normal concrete, and the compressive strength of concrete is able to exceed 100 MPa under the condition of steam curing for 8 hours at 85 ℃.

The compressive tests of concrete specimens suffering 0、25、50、75 and 100 cycles of freezing and thawing respectively in 3.5% sodium chloride solution imitated seawater were completed,using the large static-dynamic triaxial test system for concrete. The influence of cycles of freezing and thawing on the compressive strength of concrete,elastic modulus and stress-strain relationship is tested,and the concise mathematics formula is established.

This paper introduces the ultrasonic-rebound comprehensive testing method used for determination of concrete strength, analyzes the relationship be tween the strength obtained by using ultrasonic-rebound comprehensive testing m ethod and the compressive strength of concrete, and also analyzes the influence of the water ratio, steel ratio and other factors on the strength obtained by us ing ultrasonic-rebound comprehensive testing method.

Study on the coarse asgregate from a sandpit, Beijing shows that compressive strength of concrete containing the agsregate was decreased 10 to 20 MPa when unit alkali content of concrete was 6. 0kg/m3. And the strength was decreased 25 MPa when unitalkali Content was 9. 0/m3. Micro-analysis illustrates there existed the characteristics of alkali-aggregate reaction inner aggreggate and in the edge of the aggregate of above concrete specimeus

On the basis of experimental observation and analysis of taxial stress-strain curves of normal and high strength concrete,we can know:the higher the compressive strength of concrete,the larger the elasticity modules of concrets.

Based on the theoretical model of carbonation and analysis on plenty of spot data and weather data, the model of predicting average carbonation depth is proposed This model takes the compressive strength of concrete as the main parameter, and considers influence of temperature, moisture , and concentration of carbon dioxide Taking into account the randomicity of the carbonated process, the random model of predicting the carbonated concrete depth is presented in the basis of the preceding model At last, this random model is validated by spot date

Two types of core samples with dimension of 100 mm and 70 mm in diameter are prepared,which were cored from high strength concrete of 50～90 MPa compressive strength. Then,their compressive strength were measured and compared with cubic compressive strength of concrete under same curing conditions.

Passively confined tests of axial dynamic compressive strength of concrete

Currently, there is no single method for nondestructive determination of compressive strength of concrete.

The aggregate content mainly acts as a filler but also influences the compressive strength of concrete.

The compressive strength of concrete for the first group of six columns was about 40 MPa, whereas concrete with a compressive strength of about 60 MPa was used in the other six columns.

The experimentally obtained average compressive strength of concrete was 30?MPa.

Presented in this paper are results of experimental studies of the effect of water-reduclng retarder 3FG—2on the setting time of concrete and cement paste as well as the effect on“peak time”(time to reach maximum temperature)of job concrete. Through the use of the water-reduclng retarder 3FG—2 in a small scale concrete job it was shown that water content of concrete might be reduced as much as about 15 per cent and compressive strength of concrete increased about 30 per cent at age of 28 days or cement...

Presented in this paper are results of experimental studies of the effect of water-reduclng retarder 3FG—2on the setting time of concrete and cement paste as well as the effect on“peak time”(time to reach maximum temperature)of job concrete. Through the use of the water-reduclng retarder 3FG—2 in a small scale concrete job it was shown that water content of concrete might be reduced as much as about 15 per cent and compressive strength of concrete increased about 30 per cent at age of 28 days or cement cont- ent of concrete might be reduced about 15 per cent without affecting the compressive strength of concrete. Continuous experimental work both in laboratory and in field on water-reduclng retarder 3FG—2 resulst a further helpful knowledge con- cerning it and raises the confidence of its use on the job.Significant advantages are obtaind with the use of this water-reducing retarder in job concrete particulary in warm weather.

In this paper the optimum design of the temperature control for mass concrete dams has been researched by using the non-linear programme. The optimum design is considering the minimum relative construction costs as the principle, taking x1 (the compressive strength of concrete) ,x2 (drop placing temperature by adding ice to mix water),x3 ( drop placing temperature by precooling aggregate of concrete),x4 (drop temperature of concrete by initial cooling) ,x5 ( number of concrete blocks...

In this paper the optimum design of the temperature control for mass concrete dams has been researched by using the non-linear programme. The optimum design is considering the minimum relative construction costs as the principle, taking x1 (the compressive strength of concrete) ,x2 (drop placing temperature by adding ice to mix water),x3 ( drop placing temperature by precooling aggregate of concrete),x4 (drop temperature of concrete by initial cooling) ,x5 ( number of concrete blocks ) and x6 ( the lift thickness of placing)as variables. For some variables are integeral and discontinuous, the problems were solved by mesh method and complex method. FORTRAN-IV computer programs have been made and examples of their application in engineering are given. The program may be widely used in designs and constructions.

In this paper, several factors that influenced the cross-sectional ductility (such as the rate of steel content and the ratio of axial force to the compressive strength of concrete etc.) are studied here through the experiments of 38 reinforced ceramite concrete beams and columns. The relation between the moment-curvature and the load-displacement of the reinforced ceramite concrete members during the stage from cracking to failure have been tested and the results are being discussed here....

In this paper, several factors that influenced the cross-sectional ductility (such as the rate of steel content and the ratio of axial force to the compressive strength of concrete etc.) are studied here through the experiments of 38 reinforced ceramite concrete beams and columns. The relation between the moment-curvature and the load-displacement of the reinforced ceramite concrete members during the stage from cracking to failure have been tested and the results are being discussed here. According to the experiment results, the empirical formulas of the ductility ratio of the displacement of the reinforced ceramite concrete members by the action of bending moment or the bending moment combined with axial force are concluded here. The complete moment-curvature curves are obtained from theoretical analysis by using electronic computer, and they are almost in agreement with the experimental curves.