Partially Replacing the Emulsified Asphalt in Cement Emulsified Asphalt Mortars with Epoxy Emulsion: Mechanical Properties and Durability Study

Cement emulsified asphalt (CEA) mortars achieve insufficient bond strength with substrate cement concrete slab. To ameliorate problems emerging from this, the emulsified asphalt (EA) in CEA mortars was partly replaced by epoxy emulsion (EE) at contents of 0%, 10%, 20%, and 30%, yielding CEA mortars with enhanced properties. The bond strength, mechanical strength, toughness, and durability (including drying shrinkage and erosion resistance) of modified CEA mortars were assessed. The results showed that partial replacement of EA with EE improved the bond strength, mechanical strength, drying shrinkage, and erosion resistance of CEA mortars. A good correlation was found between the proportions of the EE replacement and the bond strength of CEA mortars. Partial replacement of EA with a small amount of EE exerted no significant effect on the toughness of CEA mortar. The stronger network structure of CEA mortars containing EE improved the compactness, thus improving the performance of CEA mortars. Based on these findings, EE is suggested as partial replacement of EA for enhancing the properties of CEA mortars.

Application of an Acrylic Polymer and Epoxy Emulsion to Red Clay and Sand

The use of nontraditional soil stabilizers increases. Various new soil binding agents are under study to augment renewability and sustainability of an earth structure. However, despite increasing interest involved in red clay, there is minimal research investigating the stabilizing red clay with polymer. This paper presents the findings obtained by applying the acrylic polymer and epoxy emulsion as binding agent for red clay and that for sand. The epoxy–hardener ratio, amount of epoxy emulsion, and amount of polymer aqueous solution were manipulated to quantify their effects on red clay and sand, respectively. After compacting a pair of cylindrical samples of which diameter and height are 5 cm and 10 cm, respectively, it is cured for 3 and 7 days in a controlled condition. Each pair is produced to represent the engineering performance at each data point in the solution space. An optimal composition of the binding agents for red clay and that for sand mixture are identified by experimenting every data point. In addition, given lime into each sample, the maximum unconfined compressive strength (UCS) endured by red clay sample and that by sand sample are 2243 and 1493 kPa, respectively. The UCS obtained by the sample mixed with clay and sand reaches 2671 kPa after seven days of curing. It confirms that the addition of lime remarkably improves the UCS. When the clay–sand mixture, of which the ratio is 70:30, includes 5% lime, the UCS of the mixture outperforms. Indeed, these findings, i.e., the optimal proportion of components, may contribute to the increase of initial and long-term strength of an earth structure, hence improving the renewability and sustainability of the earth construction method.

A simple way to synthesize nano-scale stable epoxy emulsion for sizing CF/epoxy composites

A simple method to prepare emulsifier was proposed to form stable nano size emulsion as sizing agent to enhance the interfacial bonding strength between carbon fiber (CF) and epoxy resin....

Performance Evaluation of Red Clay Binder with Epoxy Emulsion for Autonomous Rammed Earth Construction

Existing rammed earth construction methods have disadvantages such as increased initial costs for manufacturing the large formwork and increased labor costs owing to the labor-intensive construction techniques involved. To address the limitations of the existing rammed earth construction methods, an autonomous rammed earth construction method was introduced herein. When constructing an autonomous rammed-earth construction method, an alternative means of assuring the performance at the initial age of the binder in terms of materials is needed. In this study, in order to satisfy the performance of the red clay binder, epoxy emulsion was added to analyze the compressive strength, water loosening, shrinkage, rate of mass change, and microstructure in the range of the initial age. As a result of the analysis, the applicability of the epoxy emulsion was confirmed as a new additive for application to an autonomous rammed-earth construction method.

Performance Evaluation of Red Clay Binder with Epoxy Emulsion for Autonomous Rammed Earth Construction

Existing rammed earth construction methods have disadvantages such as increased initial costs for manufacturing the large formwork and increased labor costs owing to the labor-intensive construction techniques involved. To address the limitations of existing rammed earth construction methods, an autonomous rammed earth construction method is introduced herein. As this autonomous rammed earth construction method uses a modular formwork, alternative materials must be used in the construction to satisfy the requirements for the early-age binder performance. Accordingly, this study evaluates the use of an epoxy emulsion composed of epoxy and a hardener to enhance the performance of the binder. Preliminary experiments were conducted to determine the optimal formulation of the epoxy emulsion, following which the compressive strength, water loosening, shrinkage, rate of mass change, and microstructure of several red clay binder specimens with and without epoxy emulsion were analyzed at early ages. The results confirmed that the epoxy emulsion can be applied to satisfy the performance requirements for autonomous rammed earth construction by improving the durability and strength of the binder at early ages.

Effect of GO on DC Insulation Properties of Epoxy Composites and Its Application in Anticorrosive Coatings

Due to the fact that surfactant in epoxy emulsion can increase electron migration during electrochemical corrosion protection, which reduces the bulk resistivity of epoxy resin, the performance of water-soluble epoxy anticorrosive coatings cannot meet the normal use requirements, which restricts the progress of waterborne anticorrosive coatings. In this paper, GO was used as filler to modify epoxy emulsion to improve DC breakdown performance of polymer composite and reduce leakage current of composite under electric field. The test results showed that when KH550 modified multilayer GO was added to epoxy resin, the neutral salt spray resistance time of the coating was 600 h when the powder addition amount was 1.2 wt%. The initial corrosion voltage was –0.6832 V by Tafel curve test. At this point, the DC breakdown voltage of 35 kV/mm, compared to the pure epoxy resin was increased by 140%, the volume resistivity of 5 × 1016 Ωm., compared to the pure epoxy resin increased two orders of magnitude. It was found that although GO is conductive, a well-dispersed modified GO can be formed into a capacitive structure in epoxy resins, which has the ability to store charge, thereby reducing the leakage current of the material under the electric field and blocking the electronic path. Although this structure has little significance for the application of traditional insulation materials, in the field of anticorrosive coatings, this characteristic of reducing leakage current can assist materials to weaken the occurrence of electrochemical corrosion. Meanwhile, the excellent chemical stability and physical isolation ability of graphene can also guarantee the anticorrosive performance of coatings.