Polymer-cement Composites Research Articles

Mix proportion and properties of fire-resistant wet-mixed high-strength polypropylene fiber-reinforced sprayed polymer cement composites

This study examined the optimal mix proportions and performance of a fire-resistant wet-mixed high-strength fiber-reinforced polymer cement composite that enhances the fire-resistance of underground structures . A mix ratio was determined through preliminary tests to satisfy the target compressive strength and maintain the minimum thermal conductivity . A mix with 10% silica fume , 30% perlite replacement ratios and 0.2% of polypropylene fiber satisfied the desired standards. The polymer cement composite had high compressive, flexural, and bond strengths of approximately 40, 5, and 1.6 MPa, which are sufficient for the surface pressures encountered in road and railway tunnels.

Study of Polymer-Cement Composite Containing Portland Cement and Aqueous Poly (methyl methacrylate) Latex Polymer by Fourier-Transform Infrared (FT-IR) Spectroscopy

The polymer-cement composite is an immiscible band having modified morphology. Polymer phase improves the toughness of brittle cement and has a reinforcing effect, and interactions between cement components and polymers provide stability. In this study, polymer latex [poly(methyl methacrylate), PMMA] – cement paste was prepared with different weight proportions of polymer content. The main scientific objective of this report has been the analysis and the prediction of high strength with the aim of understanding the interactions of PMMA polymer with Portland cement after hydration reaction of cement pastes and curing the specimens for 28 days. The samples were studied by Fourier transform infrared (FT-IR) spectroscopy. The results are critically examined. It is shown that bands support the interaction of PMMA with cement in the composite.

Adhesion Strength and Other Mechanical Properties of SBR Modified Concrete

Polymer-cement composites are known repair materials. The aim of this work is to investigate the influence of various amount of dispersion of carboxylated styrene-butadience copolymer on the selected mechanical properties of polymer-cement concrete (PCC) and on its adhesion to ordinary concrete. The compressive, flexural and tensile strengths as well as frost resistance and fracture resistance of the composites are tested. Adhesion strength of PCC to ordinary concrete, as one of most important performance of good repair material is evaluated and analyzed using three test methods. The results obtained in standard pull-off test are compared with the two other tests. The first one, which is an adaptation of WST (wedge splitting test) characterizes crack propagation in the plane of bond created during repair. In the second test the resistance to shear is a measure of adhesion strength.

Utilization of emulsion polymer for preparing bagasse fibers polymer–cement composites

AbstractSugarcane‐bagasse fiber–polymer cement composites were prepared using three lattices namely, styrene butadiene, vinyl ester, and styrene acrylic. The lattices percentages ranged between 3 and 21% from the weight of the mixture. The pressed samples were irradiated at different irradiation doses by using electron beam (EB) accelerator. Comparative studies have been made for physicomechanical properties of unirradiated and irradiated samples. The results indicated that the flexural strength, modulus of elasticity, and impact toughness of the composites increase with the increasing polymer content up to 9.9 and 15% of styrene butadiene, vinyl ester, and acrylic styrene, and then decrease. It was also observed that the maximum values of flexural strength and modulus of elasticity obtained at EB‐irradiation dose 45, 40, and 25 kGy for styrene butadiene, acrylic ester, and vinyl ester, respectively. The impact strength of the composites did not significantly improve above 10 kGy. The average values of hardness of irradiated composites were higher than that those of unirradiated and control composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

New covalent bonded polymer–calcium silicate hydrate composites

New covalent bonded polymer–calcium silicate hydrate (C–S–H) composites were prepared. For this purpose, two sets of hydrosoluble copolymers, both containing trialkoxysilane (T-silane) and/or methyldialkoxysilane (D-silane) functions, were synthesized. The addition of these polymers during the synthesis of C–S–H by the sol–gel method allowed us to obtain hybrid materials. The influence of different synthesis parameters, such as the silane content and the nature of the silane functions grafted to the polymer backbone, was studied. Characterisation of the composite materials by thermogravimetry and elemental analysis showed that chemical interaction of polymers and C–S–H is due only to the presence of T-silane functions. 29Si CP MAS NMR analysis confirmed the existence of covalent linkages between the inorganic silicate chains of the C–S–H crystallites and the T-silane functions. The specific incorporation of these new classes of silane-modified polymers in C–S–H structure may be successfully used in the preparation of new polymer–cement composites with reinforced mechanical properties.

Corrosion performance of coated reinforcing bars embedded in concrete and exposed to natural marine environment

Corrosion behavior of mild steel plain bar embedded in concrete with 28 days compressive strength of 40 N/mm 2 exposed to natural marine environment at a location in the Gulf of Mannar was studied. This paper reports the results of 1-year study conducted on the reinforced concrete specimens exposed to three different levels. The performance of three different types of corrosion protection by specialty coatings to rebars, namely cement polymer composite, interpenetrating polymer network coating and epoxy coating was also evaluated periodically by measuring open circuit potential measurements and the results are discussed. Biofouling was predominant on completion of 3 months immersion.

Physico-chemical characteristics of some polymer cement composites

The electrical conductivity of cement pastes can give an indication of the initial hydration of the cement pastes and early formation of products. In this study, sulphate-resisting cement (SRC) pastes were prepared with different doses of two synthesised admixtures, namely phenol formaldehyde sulphonate (PhFS) and melamine formaldehyde sulphonate (MFS). This work is aimed to evaluate the effect of PhFS and MFS on the hydration reaction of cement pastes during the first 24 h by determining the initial, final setting times and the electrical conductivity changes, as well as the effect of these polymers on the hydration progressing up to 90 days by determining the chemically combined water content and gel/space ratio of each paste at different intervals of time (1, 3, 7, 28 and 90 days).

Preparation and characterization of absorbent polymer-cement composites

Absorbent polymer-cement composites were fabricated by casting and pressing. Homogeneity was ascertained by semidry mixing of cements with absorbent polymer-absorbed theoretical water content. Because the cement-absorbent polymer composites were fabricated using homogeneous semidry mixing at low water-to-cement ratios, their total accumulation porosity was less than 5 vol% in terms of volumetric porosity. In particular, the composites showed a very small volume of pores larger than 1 μm pore; hence, the flexural strength of composites apparently were increased over that of neat cement pastes. The average flexural strength was up to 280 kgf/cm 2 for hydrated composites with 1 wt% absorbent polymer added and cured for 28 days. When adding absorbent polymer from 0.5 to 2.0 wt% was added to Portland cement, the hydration of cement was not retarded. Because the absorbent polymer filled interparticle capillary pores and hydrates in the form of thin plate dominated, the microstructure of the absorbent polymer-cement composite was denser and the capillary pore structure changed intermittently. Accordingly, the mechanical properties of absorbent polymer-cement composite improved.

Effect of Cement on Properties of Inverted Emulsions and Polymers from Vinyl Monomers with Acid Anhydride-Adducted Polypropylene Glycol

Abstract Adduct polymer (PPGMA) prepared from polypropylene glycol and maleic anhydride was found to give stable inverted emulsions when mixtures of cement, water, and vinyl monomers were vigorously stirred in the presence of PPGMA. In this case, the carboxyl groups of PPGMA were neutralized with metal ions generated from the cement into neutralized PPGMA which acts as an effective W/O type emulsifier. The inverted emulsions containing cement gave a new type of polymer-cement composites by polymerization of the vinyl monomers and also by hardening of the cement. Water-free composites were easily obtained by removing evaporative water. The effect of cement on the physical properties of the water-free composites was remarkable. Further, the use of mixed fillers of cement and Al(OH)3 was found to improve the flame-retardant properties of the composites; however, increasing the Al(OH)3 content in the fillers resulted in a decrease in the physical properties. Generally, the composites have improved resistance to acid media in which the usual foamed hydrated cement is eroded.

Strength and deformation characteristics of an acrylic polymer-cement composite

The time-dependence of strength and deformation properties of an Acrylic polymer modified concrete has been investigated up to 600 days under wet and dry curing conditions. Ordinary Portland Cement mixes of proportion 1:2:3 (by weight) were used and the water cement ratio was adjusted in order to achieve reasonably constant workability for the control and modified mixes.