Experimental Investigation on Mechanical Properties of SBR-Modified Mortar with Fly Ash for Patch Repair Material

Abstract

This work determines the replacement ratio of fly ash of 25% in SBR-modified cement mortars based on the past research, including SBR emulsion (SBR-E) and SBR powder (SBR-P). In addition to the Japanese guidelines for the repair material, the past researches related to polymer-modified cement mortars are also used to determine an appropriate mix proportion of the patch repair material for deteriorated RC building structures. According to the experimental results in this work, it can be observed that increasing the S/W ratio of SBR is useful to improve the flexural bonding strength effectively; however, the compressive, flexural and tensile strength of cement mortars decreases. Besides of the mechanical strength, the workability and economy are considered to determine the S/W ratio of 10% of SBR-P for cement mortars with fly ash. Additionally, according to the regression results, its corresponding compressive, flexural, tensile and flexural bonding strengths are 36.5, 9.68, 3.35 and 2.8 MPa, respectively. For most of RC buildings with an age of over 30 years in Taiwan, since their average testing compressive strength is around 20 MPa, the suggested mix proportion of SBR-modified cement mortars with fly ash can provide enough performances for the patch repair.

Interface bonding properties of new and old concrete: A review

“…Wang et al found that with styreneacrylate (SAE) powder added, the bond strength of ordinary mortar increased from 0.97 to 1.3 MPa to 3.12-2.87 MPa (WANG and ZHANG, 2015). Kao et al found that adding styrene-butadiene rubber (SBR) powder to mortar resulted in a tensile strength of 3.35 MPa for repair specimens (KAO et al, 2018). When SBR polymer was added to mortar, the shrinkage measured after 1 year was 1/3 less than that of ordinary silicate cement mortar, which can significantly improve the bond strength (MOMAYEZ et al, 2005a).…”

“…The researchers found that modified mortar polymer film prepared by SAE powder had high film density and good toughness. It was more suitable as a repair material than SAE emulsion (WANG and ZHANG, 2015;KAO et al, 2018). However, in underwater conditions, the poor performance of polymer mortar affects bond strength (QIAN et al, 2016).…”

Nghiên cứu thực nghiệm về khả năng chịu lực của cột bê tông cốt thép sử dụng tro bay khi chịu nén lệch tâm phẳng

“…Tro bay cũng đã được nghiên cứu để thay thế hoàn toàn xi măng (100% FA/OPC) làm chất kết dính, kết hợp với các chất hoạt hóa phù hợp để tạo ra loại bê tông geo-polymer có cường độ mẫu trụ trung bình đạt tới 50 MPa và được nghiên cứu áp dụng cho kết cấu chịu uốn [9]. Tuy nhiên, chưa có nhiều nghiên cứu ứng dụng của bê tông có tro bay thay thế một phần xi măng làm chất kết dính vào cấu kiện BTCT chịu nén uốn [10][11][12][13][14][15][16][17].…”

Determination of Reinforced Fly Ash Concrete Columns’ Resistance Using Nonlinear Models of Materials

“…In the current global trend of sustainable construction, the utilization of industrial by-product such as fly ash (FA) for concrete to reduce the production of ordinary Portland cement (OPC) has attracted researchers' attentions for a few decades. Initially, FA was mostly utilized as an additive with a limit dose for the concrete admixture to improve workability of fresh concrete [13][14][15][16][17][18][19][20]. The actual FA amount used varies widely depending on the application, mechanical and chemical properties of FA, specification limits, as well as on the geographic location and climate.…”