Effect of Water-Cement Ratio on Pore Structure and Strength of Foam Concrete

Zhongwei Liu,Kang Zhao,Chi Hu,Yufei Tang

doi:10.1155/2016/9520294

Zhongwei Liu, Kang Zhao + Show 2 more

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https://doi.org/10.1155/2016/9520294

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Abstract

Foam concrete with different dry densities (400, 500, 600, 700, and 800 kg/m3) was prepared from ordinary Portland cement (P.O.42.5R) and vegetable protein foaming agent by adjusting the water-cement ratio through the physical foaming method. The performance of the cement paste adopted, as well as the structure and distribution of air pores, was characterized by a rheometer, scanning electron microscope, vacuum water saturation instrument, and image analysis software. Effects of the water-cement ratio on the relative viscosity of the cement paste, as well as pore structure and strength of the hardened foam concrete, were discussed. Results showed that water-cement ratio can influence the size, distribution, and connectivity of pores in foam concrete. The compressive strength of the foam concrete showed an inverted V-shaped variation law with the increase in water-cement ratio.

Highlights

Foam concrete has been widely used in roofing materials, wall materials, sound absorbing materials, underground backfill, and other applications because of the material’s characteristic light weight, good thermal insulation, excellent seismic behavior, and low noise and pollution [1]
At present, related studies mainly focus on the effect of admixture on the performance of foam concrete [2,3,4,5], as well as the correlation of pore structure and absolute dry density of foam concrete with the material’s strength, thermal conductivity, and sound absorption. w/c ratio is an important factor that influences foam concrete performance [6,7,8,9,10,11]
Jiang et al [13] investigated the effect of w/c ratio on the pore structure of high-porosity foam concrete

Summary

Introduction

Foam concrete has been widely used in roofing materials, wall materials, sound absorbing materials, underground backfill, and other applications because of the material’s characteristic light weight, good thermal insulation, excellent seismic behavior, and low noise and pollution [1]. Few studies have discussed the influences of w/c ratio on the pore structure and performance of ordinary foam concrete (porosity < 85%) [15]. Wei et al [22] investigated the coagulation and hardening behaviors of foam concrete and discovered that shortening the coagulation time by accelerating hydration can effectively enhance foam concrete stability. These works have analyzed many factors influencing the pore structure of ordinary foam concrete and the effect of w/c ratio on high-porosity foam concrete, none explored the effect of w/c ratio on the pore structure of ordinary foam concrete. Results could provide reference for the preparation of lightweight, high-strength foam concrete

Experimental

Results and Discussion

Conclusions