This present study aims to assess the effect of mixing Taal volcanic ash (TVA) as an aluminosilicate material in geopolymer (GP) mortar. Specifically, it examines various mortar properties such as compressive strength, microstructure, thermal, and radiation shielding as an effective barrier for X-ray and gamma-ray energies. In this investigation, the mixed proportion of the samples includes an S/B ratio of 0.5, an A/B ratio of 1.0, and an SP/VA ratio of 0.02. Using an automatic compression tester, the recorded maximum compressive strength of 7.73 MPa from TVA-based GP mortar revealed that pre-curing of the samples resulted in an overall gain in the average compressive strength of the samples. Following the British Standards, the modes of failure showed hourglass-shaped from vertical crack propagation and brittle failure during post-compression. From the XRD, minerals of anorthite and albite from plagioclase feldspar series pre-dominated both TVA-based GP mortar and its precursor. In the FTIR, spectra the spectral band at 459-572 cm−1 was due to the presence of silicate in geopolymer samples, and at 1200 cm−1 denoted the anorthite mineral presented and identified also in diffractograms. The significant shift from TVA and GP mortar in this spectral band can be attributed to the extent of the chemical reaction during geopolymerization. Meanwhile, a maximum loss of 9.77 % can be accounted to the removal of ‒OH groups from the N-A-S-H gel product. The surface morphology images revealed a degree of geopolymerization, although not optimally, took place from the precipitate formed around the TVA which can be linked to the coarseness of the particles leading to low reactivity. This can be solved by extending the grinding and sieving process of TVA prior to mixing it in the GP. Regarding radiation shielding parameters interpolated and done by EpiXS software, MACs and LACs were seen the highest in favor of GP mortar, while the lowest thickness for both MFP and HVL. High Neff and Zeff values were also observed from GP mortar which was attributed to the presence of a high amount of Fe. Lastly, the EABF and EBF plots displayed higher values at 40 MFP occurred at the intermediate-energy region due to the photon absorption, Compton scattering, and secondary radiations. The results suggest that utilizing a TVA-based geopolymer provided good performance for radiation shielding applications, although compressive strength can still be improved further.

中文翻译：

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评估塔尔火山灰基地质聚合物砂浆的抗压强度、微观结构、热和辐射屏蔽性能


本研究旨在评估将塔尔火山灰 （TVA） 作为铝硅酸盐材料混合在地质聚合物 （GP） 砂浆中的影响。具体来说，它研究了各种砂浆特性，例如抗压强度、微观结构、热和辐射屏蔽作为 X 射线和伽马射线能量的有效屏障。在这项研究中，样本的混合比例包括 S/B 比为 0.5、A/B 比为 1.0 和 SP/VA 比为 0.02。使用自动压缩测试仪，基于 TVA 的 GP 砂浆记录的最大抗压强度为 7.73 MPa，这表明样品的预固化导致样品的平均抗压强度总体提高。按照英国标准，破坏模式因垂直裂纹扩展和后压缩过程中的脆性破坏而呈现沙漏状。从 XRD 来看，来自斜长石系列的钙长石和钠长石矿物在基于 TVA 的 GP 砂浆及其前驱体中占主导地位。在 FTIR 中，光谱位于 459-572 cm-1 处的光谱带是由于地质聚合物样品中存在硅酸盐，而在 1200 cm-1 处表示在衍射图中呈现和鉴定的钙长石矿物。TVA 和 GP 砂浆在该光谱带中的显著变化可归因于地聚合过程中化学反应的程度。同时，从 N-A-S-H 凝胶产品中去除 \u2012OH 基团的最大损失为 9.77%。表面形态图像显示，一定程度的地聚合作用（尽管不是最佳）发生在 TVA 周围形成的沉淀物中，这可能与颗粒的粗大性有关，从而导致低反应性。这可以通过在 GP 中混合 TVA 之前延长 TVA 的研磨和筛分过程来解决。 关于由 EpiXS 软件插值和完成的辐射屏蔽参数，MAC 和 LAC 被认为最高，有利于 GP 砂浆，而 MFP 和 HVL 的厚度最低。从 GP 砂浆中也观察到高 Neff 和 Zeff 值，这归因于大量 Fe 的存在。最后，由于光子吸收、康普顿散射和二次辐射，EABF 和 EBF 图显示 40 MFP 时在中等能区域出现更高的值。结果表明，利用基于 TVA 的地质聚合物为辐射屏蔽应用提供了良好的性能，尽管抗压强度仍可进一步提高。