BP Network Based Mix Proportion Design of Self-Compacting Concrete
It was known that many parameters of raw materials, such as, strength of cement, mud content and modulus of fineness of river sand, maximum size of aggregate, content of' needle-like/sheet-like crushed stone, loss of ignition and fineness of fly ash, may exert significant influence on the theology and mechanical properties of self compacting concrete(SCC). It is a dream of researchers to identify the influencing degree of various factors on performance of SCC so as to obtain optimal properties. By virtue of BP neural network approach, this paper employed strength of cement, mud content and fineness modulus of fineness of river sand, maximum size of aggregate, content of needle-like/sheet-like crushed stone, loss of ignition and fineness of fly ash as the input parameters, and the corresponding optimized mix proportion as the output to describe the nonlinear relationship between them. And the orthogonal experiment was designed for the purpose of training and verification of network. The results demonstrated that the pre-trained BP neural network trained by orthogonal test data may employ to predict the optimal concrete mix proportion. This approach may replace some waste-time and heavy laboratory tests. In addition, such method may real-time optimize mixture proportion. of self-compacting concrete, which has great effect on the quality control of manufacturing self-compacting concrete.
STUDY ON THE APPLICATION OF BACK PROPAGATION NEURAL NETWORK TO CONFECT HIGH STRENGTH CONCRETE
Based on the theory of neural network. the technical experiences and route of the compounding and construction in high strength pumping concrete, the author suggests a BP neural network approach to solve the problems of modular ambiguity, the multiple random factors and the nonlinear influence of the composition to the strength of the concrete. Accordingly, he develops an applicable software for mix proportion of concrete which is capable of forecasting the strength and the workability of the high strength concrete. \[
Fly Ash Concrete Mix Design and the Water-Cement Ratio Law
When the water-cement ratio law was proposed by Abrams in 1918, the use of fly ash and silica fume as replacements or substitutes for part of the cement was virtually unknown. Consequently, the effects of fly ash and silica fume were not considered in the development of Abrams' law. Since the early 1960s, concrete mix compositions have changed, and cement is no longer the only cementitious material in concrete mixes. In a high percentage of situations, today's cementitious material content is made up of cement plus fly ash. This study investigates the applicability of Abrams' law to concrete mixes containing fly ash. As initially expected, it was found that Abrams' water-cement ratio law is not directly applicable to mixes with fly ash. An alternative augmented water-cementitious materials ratio law is proposed for designing concrete mixes containing fly ash.