Development of novel lightweight mud phuska composite using less cohesive soil, agricultural and rubber aggregates for roof and wall treatment

Introduction: The construction of an energy-efficient building that satisfies all of the customer's requirements is in high demand (1). The modern buildings have most severe issues with poor indoor environmental quality, thermal comfort, and low efficiency. The current paper presents the usefulness of crumb rubber added Mud phuska thermal insulating composites. Rubber tire aggregates in the form of crumb rubber (through cryogenic grinding), was added in different proportion into cement- soil mixes, along with other kind of agricultural wastes (Wheat straw, Baggase/ Sugarcane waste). The Physico-mechanical and thermal performance (k value) of the built composites were investigated in this research.

Methods: Local soil, OPC-43 grade cement, Agriculture waste (wheat straw, sugarcane waste and crumb rubber powder) were selected to develop cement stabilized mud composites. In this case, the major task was to stabilize the less cohesive soil by adding OPC-43 cement in different proportion, ranging from 5% to 15% by weight of soil. It was concluded that 10% of cement was enough to stabilize soil samples. In total, 30 mix-proportions were made by replacement and addition of wheat Straw, crumb rubber and bagasse (Figure 1). Dry density, compressive strength and thermal behaviour was determined after 7 and 28 days of curing.

Results & Discussions: Dry density was calculated after 28 days of curing, and then density with its strength was correlated. As per IS 3792:1987 (2); the density was directly proportional to the k value. It was found that the sample having less water binder ratio showed more compressive strength. Further; the mud composite blocks were compared with brick of class III. It was also found that the result was very much support the idea of using developed mud composites tiles over the roof of building for providing better thermal performance. For determining the effectiveness of crumb rubber blended mud composites tiles and bricks; two model houses were constructed. Based on this research study, it was inferred that using mud composites tiles over the roof, keeps the house cooler in summer during day and night.

Conclusions:  After casting the cubes of size 50mm, two types of curing were performed viz.- water curing and moist curing and observed that moist cured samples showed good results as compared to water cured samples. The experimental observations revealed that the mix proportion with ratio of crumb rubber and wheat straw in soil and cement mix up to 7.5%, has achieved the desired value of compressive strength (2.65 MPa) and k value (0.25 W/m.K). It was discovered that house with cement stabilized mud composites (masonry blocks and tiles) was cooler than the traditional model house, with an average temperature difference of 4-6⁰ C.

Keywords: Cement stabilized mud composites, Mud phuska tiles, Wheat straw, Baggase, Crumb rubber.

Acknowledgment: The authors are thankful to Director, CSIR-CBRI, Roorkee (Uttarakhand) for granting permission to publish this research paper. The financial supports from ‘Ministry of Environment, Forest and Climate Change, New Delhi, Government of India’ (File Number: 19-45/2018/RE; Project No.: GAP0090) are gratefully acknowledged. 

References              

1. Huang Y, Niu JL, Chung TM, Study on performance of energy-efficient retrofitting measures on commercial building external walls in cooling-dominant cities. Appl. Energy. 2013; 103: 97–108. https://doi.org/10.1016/j.apenergy.2012.09.003 

2. IS 3792, Guide for heat insulation of non-industrial buildings. Bureau of Indian Standards, 1987.