The design versatility of cement-based composites continues to make them attractive for a variety of specialized applications. Advanced processing techniques, including the Hatschek process, extrusion, self-consolidating concrete and slipform-cast concrete paving, offer great promise for improving innovation in the modern construction world. However, to advance the state-of-theart of cement-based products, the fresh state characteristics of these materials need to be well understood. Processing has a significant impact on composite performance, affecting fresh and hardened state properties as well as overall cost. In spite of its importance, relatively little is known about the relationship between processing and composite performance. Recent work at the Center for Advanced Cement-Based Materials (ACBM), headquartered at Northwestern University, has focused on developing a better understanding of this critical relationship. The role of processing on composite performance has been examined for a variety of advanced processing techniques, including the Hatschek process, extrusion, self consolidating concrete and slipform-cast concrete paving. The results indicate that overall composite performance can be enhanced by controlling fresh state properties. This paper presents a review of these studies and discusses ongoing research to link composite performance to microstructural changes.

This paper presents an analytical model developed to predict the flexural response of a novel thin-walled pole comprising centrifugally cast concrete into a glass fiber reinforced polymer (GFRP) circular tube. The tube acts as a permanent form and at the same time is effectively considered as reinforcement for the pole by means of layers of fibers oriented in the longitudinal and circumferential directions. The model combines cracked-section analysis, the classical lamination theory of composites and non-linear extended strain softening concrete models, through a layer-bylayer approach to account for the inherent complex geometry of the section. The model was verified using experimental results and showed good agreement. It was then used in a parametric study to establish the optimum concrete wall thickness for FRP tubes of different proportions of fibers in the longitudinal and circumferential directions as well as tubes of different wall thicknesses. It was shown that the optimum concrete wall thickness is highly dependent on the FRP tube composition. It increases as the fraction of longitudinal fibers increases, or as the wall thickness of the tube increases.

Thermal insulation and thermal energy storage are becoming more and more attractive for residential and industrial buildings due to the need of sustainable development. The economical and efficient technique that can be used to produce building products for insulation and store energy is also the subject of research for a long time. Cement-based products manufactured by extrusion technique offer advantages in terms of the flexibility of section profiles, material performance enhancement and mass production mode. Different fillers can be used to achieve desired effects on thermal, mechanical and physical characteristics during extrusion process. These fillers include sand and expanded perlite which are good at thermal insulation and phase change composites which can provide high energy storage capacities. It is foreseeable that extruded building products with suitable fillers have potentiality for economical applications for thermal insulation and thermal storage of different kinds of buildings.

Carbonation curing of cellulose fiberboard made by slurry-dewatering process was studied to examine their CO2 uptake capability, immediate carbonation strength and long term strength after subsequent hydration. Influencing parameters on CO2 uptake and strength gain were discussed. They included compact forming pressure, drying time, drying temperature, carbonation duration, fiber/cement ratio and water/cement ratio. It was found that cement bonded cellulose fiberboards had excellent carbonation capacity. The percent carbon uptake ranged from 13.5 % to 23.6%, based on cement content and process conditions. High degree of carbonation significantly improved early age strength and had no detrimental effect on the subsequent hydration strength. To promote more CO2 uptake and higher strength gain, carbonation rate should be controlled. This can be achieved through system optimization. Carbonation curing has shown the potential to replace traditional autoclaving and gain technical, economical and environmental benefits.

The housing industry is a critical component of the American economy representing about 4% of the economic activity of the nation. Light weight structural insulated panels (SIP) for walls and roofs are gaining wide acceptance in the construction industry because of the advantages they offer. Energy savings, sound abatement, disaster resistance and durability are just a few of the benefits of buildings constructed with SIP. A variation of these panels is a structural concrete insulated panel (SCIP), commercially referred to as the MetRock (MR) Panel system. The aim of this paper was to study the flexural behavior of the SCIP system and discuss the manufacturing and construction aspects of the SCIP system. An analytical method for estimating the panel’s flexural strength was developed and a step-by-step design procedure is provided to predict the load carrying capacity of the panels and provide the engineer with a reliable tool for designing the panels. An experimental program was conducted and the results were compared to the analytical method for different size panels. The test results were in close agreement with the estimated values thus verifying the validity of the analytical approach.